d2a7d88662
This adds a new route "t"-flag that enables network address translation, replacing the source address (and local port) of a forwarded packet to one of the outgoing interface. The state for a translation is kept in a new Translation structure, which contains two Iphash entries, so it can be inserted into the per protocol 4-tuple hash table, requiering no extra lookups. Translations have a low overhead (~200 bytes on amd64), so we can have many of them. They get reused after 5 minutes of inactivity or when the per protocol limit of 1000 entries is reached (then the one with longest inactivity is reused). The protocol needs to export a "forward" function that is responsible for modifying the forwarded packet, and then handle translations in its input function for iphash hits with Iphash.trans != 0. This patch also fixes a few minor things found during development: - Include the Iphash in the Conv structure, avoiding estra malloc - Fix ttl exceeded check (ttl < 1 -> ttl <= 1) - Router should not reply with ttl exceeded for multicast flows - Extra checks for icmp advice to avoid protocol confusions.
3479 lines
72 KiB
C
3479 lines
72 KiB
C
#include "u.h"
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#include "../port/lib.h"
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#include "mem.h"
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#include "dat.h"
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#include "fns.h"
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#include "../port/error.h"
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#include "ip.h"
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enum
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{
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QMAX = 64*1024-1,
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IP_TCPPROTO = 6,
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TCP4_IPLEN = 8,
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TCP4_PHDRSIZE = 12,
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TCP4_HDRSIZE = 20,
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TCP4_TCBPHDRSZ = 40,
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TCP4_PKT = TCP4_IPLEN+TCP4_PHDRSIZE,
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TCP6_IPLEN = 0,
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TCP6_PHDRSIZE = 40,
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TCP6_HDRSIZE = 20,
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TCP6_TCBPHDRSZ = 60,
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TCP6_PKT = TCP6_IPLEN+TCP6_PHDRSIZE,
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TcptimerOFF = 0,
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TcptimerON = 1,
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TcptimerDONE = 2,
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MAX_TIME = (1<<20), /* Forever */
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TCP_ACK = 50, /* Timed ack sequence in ms */
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MAXBACKMS = 9*60*1000, /* longest backoff time (ms) before hangup */
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URG = 0x20, /* Data marked urgent */
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ACK = 0x10, /* Acknowledge is valid */
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PSH = 0x08, /* Whole data pipe is pushed */
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RST = 0x04, /* Reset connection */
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SYN = 0x02, /* Pkt. is synchronise */
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FIN = 0x01, /* Start close down */
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EOLOPT = 0,
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NOOPOPT = 1,
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MSSOPT = 2,
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MSS_LENGTH = 4, /* Maximum segment size */
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WSOPT = 3,
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WS_LENGTH = 3, /* Bits to scale window size by */
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MSL2 = 10,
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MSPTICK = 50, /* Milliseconds per timer tick */
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DEF_MSS = 1460, /* Default maximum segment */
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DEF_MSS6 = 1220, /* Default maximum segment (min) for v6 */
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DEF_RTT = 500, /* Default round trip */
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DEF_KAT = 120000, /* Default time (ms) between keep alives */
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TCP_LISTEN = 0, /* Listen connection */
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TCP_CONNECT = 1, /* Outgoing connection */
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SYNACK_RXTIMER = 250, /* ms between SYNACK retransmits */
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TCPREXMTTHRESH = 3, /* dupack threshhold for rxt */
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FORCE = 1,
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CLONE = 2,
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RETRAN = 4,
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ACTIVE = 8,
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SYNACK = 16,
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LOGAGAIN = 3,
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LOGDGAIN = 2,
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Closed = 0, /* Connection states */
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Listen,
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Syn_sent,
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Syn_received,
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Established,
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Finwait1,
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Finwait2,
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Close_wait,
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Closing,
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Last_ack,
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Time_wait,
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Maxlimbo = 1000, /* maximum procs waiting for response to SYN ACK */
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NLHT = 256, /* hash table size, must be a power of 2 */
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LHTMASK = NLHT-1,
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/*
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* window is 64kb · 2ⁿ
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* these factors determine the ultimate bandwidth-delay product.
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* 64kb · 2⁵ = 2mb, or 2x overkill for 100mbps · 70ms.
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*/
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Maxqscale = 4, /* maximum queuing scale */
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Defadvscale = 4, /* default advertisement */
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};
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/* negative return from ipoput means no route */
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static char Enoroute[] = "no route";
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/* Must correspond to the enumeration above */
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static char *tcpstates[] =
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{
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"Closed", "Listen", "Syn_sent", "Syn_received",
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"Established", "Finwait1", "Finwait2", "Close_wait",
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"Closing", "Last_ack", "Time_wait"
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};
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typedef struct Tcptimer Tcptimer;
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struct Tcptimer
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{
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Tcptimer *next;
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Tcptimer *prev;
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Tcptimer *readynext;
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int state;
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int start;
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int count;
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void (*func)(void*);
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void *arg;
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};
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/*
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* v4 and v6 pseudo headers used for
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* checksuming tcp
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*/
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typedef struct Tcp4hdr Tcp4hdr;
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struct Tcp4hdr
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{
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uchar vihl; /* Version and header length */
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uchar tos; /* Type of service */
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uchar length[2]; /* packet length */
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uchar id[2]; /* Identification */
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uchar frag[2]; /* Fragment information */
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uchar ttl;
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uchar proto;
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uchar tcplen[2];
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uchar tcpsrc[4];
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uchar tcpdst[4];
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uchar tcpsport[2];
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uchar tcpdport[2];
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uchar tcpseq[4];
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uchar tcpack[4];
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uchar tcpflag[2];
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uchar tcpwin[2];
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uchar tcpcksum[2];
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uchar tcpurg[2];
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/* Options segment */
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uchar tcpopt[1];
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};
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typedef struct Tcp6hdr Tcp6hdr;
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struct Tcp6hdr
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{
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uchar vcf[4];
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uchar ploadlen[2];
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uchar proto;
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uchar ttl;
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uchar tcpsrc[IPaddrlen];
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uchar tcpdst[IPaddrlen];
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uchar tcpsport[2];
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uchar tcpdport[2];
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uchar tcpseq[4];
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uchar tcpack[4];
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uchar tcpflag[2];
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uchar tcpwin[2];
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uchar tcpcksum[2];
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uchar tcpurg[2];
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/* Options segment */
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uchar tcpopt[1];
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};
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/*
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* this represents the control info
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* for a single packet. It is derived from
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* a packet in ntohtcp{4,6}() and stuck into
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* a packet in htontcp{4,6}().
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*/
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typedef struct Tcp Tcp;
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struct Tcp
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{
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ushort source;
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ushort dest;
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ulong seq;
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ulong ack;
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uchar flags;
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uchar update;
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ushort ws; /* window scale option */
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ulong wnd; /* prescaled window*/
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ushort urg;
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ushort mss; /* max segment size option (if not zero) */
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ushort len; /* size of data */
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};
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/*
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* this header is malloc'd to thread together fragments
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* waiting to be coalesced
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*/
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typedef struct Reseq Reseq;
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struct Reseq
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{
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Reseq *next;
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Tcp seg;
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Block *bp;
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ushort length;
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};
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/*
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* the qlock in the Conv locks this structure
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*/
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typedef struct Tcpctl Tcpctl;
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struct Tcpctl
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{
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uchar state; /* Connection state */
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uchar type; /* Listening or active connection */
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uchar code; /* Icmp code */
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struct {
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ulong una; /* Unacked data pointer */
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ulong nxt; /* Next sequence expected */
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ulong ptr; /* Data pointer */
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ulong wnd; /* Tcp send window */
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ulong urg; /* Urgent data pointer */
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ulong wl2;
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uint scale; /* how much to right shift window in xmitted packets */
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/* to implement tahoe and reno TCP */
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ulong dupacks; /* number of duplicate acks rcvd */
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ulong partialack;
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int recovery; /* loss recovery flag */
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int retransmit; /* retransmit 1 packet @ una flag */
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int rto;
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ulong rxt; /* right window marker for recovery "recover" rfc3782 */
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} snd;
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struct {
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ulong nxt; /* Receive pointer to next uchar slot */
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ulong wnd; /* Receive window incoming */
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ulong wsnt; /* Last wptr sent. important to track for large bdp */
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ulong wptr;
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ulong urg; /* Urgent pointer */
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ulong ackptr; /* last acked sequence */
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int blocked;
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uint scale; /* how much to left shift window in rcv'd packets */
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} rcv;
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ulong iss; /* Initial sequence number */
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ulong cwind; /* Congestion window */
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ulong abcbytes; /* appropriate byte counting rfc 3465 */
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uint scale; /* desired snd.scale */
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ulong ssthresh; /* Slow start threshold */
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int resent; /* Bytes just resent */
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int irs; /* Initial received squence */
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ushort mss; /* Maximum segment size */
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int rerecv; /* Overlap of data rerecevived */
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ulong window; /* Our receive window (queue) */
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uint qscale; /* Log2 of our receive window (queue) */
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uchar backoff; /* Exponential backoff counter */
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int backedoff; /* ms we've backed off for rexmits */
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uchar flags; /* State flags */
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Reseq *reseq; /* Resequencing queue */
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int nreseq;
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int reseqlen;
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Tcptimer timer; /* Activity timer */
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Tcptimer acktimer; /* Acknowledge timer */
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Tcptimer rtt_timer; /* Round trip timer */
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Tcptimer katimer; /* keep alive timer */
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ulong rttseq; /* Round trip sequence */
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int srtt; /* Smoothed round trip */
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int mdev; /* Mean deviation of round trip */
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int kacounter; /* count down for keep alive */
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uint sndsyntime; /* time syn sent */
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ulong time; /* time Finwait2 or Syn_received was sent */
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ulong timeuna; /* snd.una when time was set */
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int nochecksum; /* non-zero means don't send checksums */
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int flgcnt; /* number of flags in the sequence (FIN,SEQ) */
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union {
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Tcp4hdr tcp4hdr;
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Tcp6hdr tcp6hdr;
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} protohdr; /* prototype header */
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};
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/*
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* New calls are put in limbo rather than having a conversation structure
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* allocated. Thus, a SYN attack results in lots of limbo'd calls but not
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* any real Conv structures mucking things up. Calls in limbo rexmit their
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* SYN ACK every SYNACK_RXTIMER ms up to 4 times, i.e., they disappear after 1 second.
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*
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* In particular they aren't on a listener's queue so that they don't figure
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* in the input queue limit.
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*
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* If 1/2 of a T3 was attacking SYN packets, we'ld have a permanent queue
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* of 70000 limbo'd calls. Not great for a linear list but doable. Therefore
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* there is no hashing of this list.
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*/
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typedef struct Limbo Limbo;
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struct Limbo
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{
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Limbo *next;
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uchar laddr[IPaddrlen];
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uchar raddr[IPaddrlen];
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ushort lport;
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ushort rport;
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ulong irs; /* initial received sequence */
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ulong iss; /* initial sent sequence */
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ushort mss; /* mss from the other end */
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ushort rcvscale; /* how much to scale rcvd windows */
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ushort sndscale; /* how much to scale sent windows */
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ulong lastsend; /* last time we sent a synack */
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uchar version; /* v4 or v6 */
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uchar rexmits; /* number of retransmissions */
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};
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int tcp_irtt = DEF_RTT; /* Initial guess at round trip time */
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enum {
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/* MIB stats */
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MaxConn,
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Mss,
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ActiveOpens,
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PassiveOpens,
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EstabResets,
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CurrEstab,
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InSegs,
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OutSegs,
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RetransSegs,
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RetransSegsSent,
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RetransTimeouts,
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InErrs,
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OutRsts,
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/* non-MIB stats */
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CsumErrs,
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HlenErrs,
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LenErrs,
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Resequenced,
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OutOfOrder,
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ReseqBytelim,
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ReseqPktlim,
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Delayack,
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Wopenack,
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Recovery,
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RecoveryDone,
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RecoveryRTO,
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RecoveryNoSeq,
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RecoveryCwind,
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RecoveryPA,
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Nstats
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};
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static char *statnames[Nstats] =
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{
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[MaxConn] "MaxConn",
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[Mss] "MaxSegment",
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[ActiveOpens] "ActiveOpens",
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[PassiveOpens] "PassiveOpens",
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[EstabResets] "EstabResets",
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[CurrEstab] "CurrEstab",
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[InSegs] "InSegs",
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[OutSegs] "OutSegs",
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[RetransSegs] "RetransSegs",
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[RetransSegsSent] "RetransSegsSent",
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[RetransTimeouts] "RetransTimeouts",
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[InErrs] "InErrs",
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[OutRsts] "OutRsts",
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[CsumErrs] "CsumErrs",
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[HlenErrs] "HlenErrs",
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[LenErrs] "LenErrs",
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[OutOfOrder] "OutOfOrder",
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[Resequenced] "Resequenced",
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[ReseqBytelim] "ReseqBytelim",
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[ReseqPktlim] "ReseqPktlim",
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[Delayack] "Delayack",
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[Wopenack] "Wopenack",
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[Recovery] "Recovery",
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[RecoveryDone] "RecoveryDone",
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[RecoveryRTO] "RecoveryRTO",
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[RecoveryNoSeq] "RecoveryNoSeq",
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[RecoveryCwind] "RecoveryCwind",
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[RecoveryPA] "RecoveryPA",
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};
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typedef struct Tcppriv Tcppriv;
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struct Tcppriv
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{
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/* List of active timers */
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QLock tl;
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Tcptimer *timers;
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/* hash table for matching conversations */
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Ipht ht;
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/* calls in limbo waiting for an ACK to our SYN ACK */
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int nlimbo;
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Limbo *lht[NLHT];
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/* for keeping track of tcpackproc */
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QLock apl;
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int ackprocstarted;
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uvlong stats[Nstats];
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};
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/*
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* Setting tcpporthogdefense to non-zero enables Dong Lin's
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* solution to hijacked systems staking out port's as a form
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* of DoS attack.
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*
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* To avoid stateless Conv hogs, we pick a sequence number at random. If
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* that number gets acked by the other end, we shut down the connection.
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* Look for tcpporthogdefense in the code.
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*/
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int tcpporthogdefense = 0;
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static int addreseq(Fs*, Tcpctl*, Tcppriv*, Tcp*, Block**, ushort);
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static int dumpreseq(Tcpctl*);
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static void getreseq(Tcpctl*, Tcp*, Block**, ushort*);
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static void limbo(Conv*, uchar*, uchar*, Tcp*, int);
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static void limborexmit(Proto*);
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static void localclose(Conv*, char*);
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static void procsyn(Conv*, Tcp*);
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static void tcpacktimer(void*);
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static void tcpiput(Proto*, Ipifc*, Block*);
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static void tcpkeepalive(void*);
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static void tcpoutput(Conv*);
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static void tcprcvwin(Conv*);
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static void tcprxmit(Conv*);
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static void tcpsetkacounter(Tcpctl*);
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static void tcpsetscale(Conv*, Tcpctl*, ushort, ushort);
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static void tcpsettimer(Tcpctl*);
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static void tcpsndsyn(Conv*, Tcpctl*);
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static void tcpstart(Conv*, int);
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static void tcpsynackrtt(Conv*);
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static void tcptimeout(void*);
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static int tcptrim(Tcpctl*, Tcp*, Block**, ushort*);
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static void
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tcpsetstate(Conv *s, uchar newstate)
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{
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Tcpctl *tcb;
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uchar oldstate;
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Tcppriv *tpriv;
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tpriv = s->p->priv;
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tcb = (Tcpctl*)s->ptcl;
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oldstate = tcb->state;
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if(oldstate == newstate)
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return;
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if(oldstate == Established)
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tpriv->stats[CurrEstab]--;
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if(newstate == Established)
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tpriv->stats[CurrEstab]++;
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switch(newstate) {
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case Closed:
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qclose(s->rq);
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qclose(s->wq);
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qclose(s->eq);
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break;
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case Close_wait: /* Remote closes */
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qhangup(s->rq, nil);
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break;
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}
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tcb->state = newstate;
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if(oldstate == Syn_sent && newstate != Closed)
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Fsconnected(s, nil);
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}
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static char*
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tcpconnect(Conv *c, char **argv, int argc)
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{
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char *e;
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Tcpctl *tcb;
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tcb = (Tcpctl*)(c->ptcl);
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if(tcb->state != Closed)
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return Econinuse;
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e = Fsstdconnect(c, argv, argc);
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if(e != nil)
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return e;
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tcpstart(c, TCP_CONNECT);
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return nil;
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}
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static int
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tcpstate(Conv *c, char *state, int n)
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{
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Tcpctl *s;
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s = (Tcpctl*)(c->ptcl);
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return snprint(state, n,
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"%s qin %d qout %d rq %d.%d srtt %d mdev %d sst %lud cwin %lud swin %lud>>%d rwin %lud>>%d qscale %d timer.start %d timer.count %d rerecv %d katimer.start %d katimer.count %d\n",
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tcpstates[s->state],
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c->rq ? qlen(c->rq) : 0,
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c->wq ? qlen(c->wq) : 0,
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s->nreseq, s->reseqlen,
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s->srtt, s->mdev, s->ssthresh,
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s->cwind, s->snd.wnd, s->snd.scale, s->rcv.wnd, s->rcv.scale,
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s->qscale,
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s->timer.start, s->timer.count, s->rerecv,
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s->katimer.start, s->katimer.count);
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}
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static int
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tcpinuse(Conv *c)
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{
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Tcpctl *s;
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s = (Tcpctl*)(c->ptcl);
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return s->state != Closed;
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|
}
|
|
|
|
static char*
|
|
tcpannounce(Conv *c, char **argv, int argc)
|
|
{
|
|
char *e;
|
|
Tcpctl *tcb;
|
|
|
|
tcb = (Tcpctl*)(c->ptcl);
|
|
if(tcb->state != Closed)
|
|
return Econinuse;
|
|
|
|
e = Fsstdannounce(c, argv, argc);
|
|
if(e != nil)
|
|
return e;
|
|
tcpstart(c, TCP_LISTEN);
|
|
Fsconnected(c, nil);
|
|
|
|
return nil;
|
|
}
|
|
|
|
/*
|
|
* tcpclose is always called with the q locked
|
|
*/
|
|
static void
|
|
tcpclose(Conv *c)
|
|
{
|
|
Tcpctl *tcb;
|
|
|
|
tcb = (Tcpctl*)c->ptcl;
|
|
|
|
qhangup(c->rq, nil);
|
|
qhangup(c->wq, nil);
|
|
qhangup(c->eq, nil);
|
|
qflush(c->rq);
|
|
|
|
switch(tcb->state) {
|
|
case Listen:
|
|
/*
|
|
* reset any incoming calls to this listener
|
|
*/
|
|
Fsconnected(c, "Hangup");
|
|
|
|
localclose(c, nil);
|
|
break;
|
|
case Closed:
|
|
case Syn_sent:
|
|
localclose(c, nil);
|
|
break;
|
|
case Syn_received:
|
|
case Established:
|
|
tcb->flgcnt++;
|
|
tcb->snd.nxt++;
|
|
tcpsetstate(c, Finwait1);
|
|
tcpoutput(c);
|
|
break;
|
|
case Close_wait:
|
|
tcb->flgcnt++;
|
|
tcb->snd.nxt++;
|
|
tcpsetstate(c, Last_ack);
|
|
tcpoutput(c);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void
|
|
tcpkick(void *x)
|
|
{
|
|
Conv *s = x;
|
|
Tcpctl *tcb;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
|
|
if(waserror()){
|
|
qunlock(s);
|
|
nexterror();
|
|
}
|
|
qlock(s);
|
|
|
|
switch(tcb->state) {
|
|
case Syn_sent:
|
|
case Syn_received:
|
|
case Established:
|
|
case Close_wait:
|
|
/*
|
|
* Push data
|
|
*/
|
|
tcpoutput(s);
|
|
break;
|
|
default:
|
|
localclose(s, "Hangup");
|
|
break;
|
|
}
|
|
|
|
qunlock(s);
|
|
poperror();
|
|
}
|
|
|
|
static int seq_lt(ulong, ulong);
|
|
|
|
static void
|
|
tcprcvwin(Conv *s) /* Call with tcb locked */
|
|
{
|
|
int w;
|
|
Tcpctl *tcb;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
w = tcb->window - qlen(s->rq);
|
|
if(w < 0)
|
|
w = 0;
|
|
/* RFC 1122 § 4.2.2.17 do not move right edge of window left */
|
|
if(seq_lt(tcb->rcv.nxt + w, tcb->rcv.wptr))
|
|
w = tcb->rcv.wptr - tcb->rcv.nxt;
|
|
if(w != tcb->rcv.wnd)
|
|
if(w>>tcb->rcv.scale == 0 || tcb->window > 4*tcb->mss && w < tcb->mss/4){
|
|
tcb->rcv.blocked = 1;
|
|
netlog(s->p->f, Logtcp, "tcprcvwin: window %lud qlen %d ws %ud lport %d\n",
|
|
tcb->window, qlen(s->rq), tcb->rcv.scale, s->lport);
|
|
}
|
|
tcb->rcv.wnd = w;
|
|
tcb->rcv.wptr = tcb->rcv.nxt + w;
|
|
}
|
|
|
|
static void
|
|
tcpacktimer(void *v)
|
|
{
|
|
Tcpctl *tcb;
|
|
Conv *s;
|
|
|
|
s = v;
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
|
|
if(waserror()){
|
|
qunlock(s);
|
|
nexterror();
|
|
}
|
|
qlock(s);
|
|
if(tcb->state != Closed){
|
|
tcb->flags |= FORCE;
|
|
tcpoutput(s);
|
|
}
|
|
qunlock(s);
|
|
poperror();
|
|
}
|
|
|
|
static void
|
|
tcpcongestion(Tcpctl *tcb)
|
|
{
|
|
ulong inflight;
|
|
|
|
inflight = tcb->snd.nxt - tcb->snd.una;
|
|
if(inflight > tcb->cwind)
|
|
inflight = tcb->cwind;
|
|
tcb->ssthresh = inflight / 2;
|
|
if(tcb->ssthresh < 2*tcb->mss)
|
|
tcb->ssthresh = 2*tcb->mss;
|
|
}
|
|
|
|
enum {
|
|
L = 2, /* aggressive slow start; legal values ∈ (1.0, 2.0) */
|
|
};
|
|
|
|
static void
|
|
tcpabcincr(Tcpctl *tcb, uint acked)
|
|
{
|
|
uint limit;
|
|
|
|
tcb->abcbytes += acked;
|
|
if(tcb->cwind < tcb->ssthresh){
|
|
/* slow start */
|
|
if(tcb->snd.rto)
|
|
limit = 1*tcb->mss;
|
|
else
|
|
limit = L*tcb->mss;
|
|
tcb->cwind += MIN(tcb->abcbytes, limit);
|
|
tcb->abcbytes = 0;
|
|
}
|
|
else{
|
|
tcb->snd.rto = 0;
|
|
/* avoidance */
|
|
if(tcb->abcbytes >= tcb->cwind){
|
|
tcb->abcbytes -= tcb->cwind;
|
|
tcb->cwind += tcb->mss;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
tcpcreate(Conv *c)
|
|
{
|
|
c->rq = qopen(QMAX, Qcoalesce, tcpacktimer, c);
|
|
c->wq = qopen(QMAX, Qkick, tcpkick, c);
|
|
}
|
|
|
|
static void
|
|
timerstate(Tcppriv *priv, Tcptimer *t, int newstate)
|
|
{
|
|
if(newstate != TcptimerON){
|
|
if(t->state == TcptimerON){
|
|
/* unchain */
|
|
if(priv->timers == t){
|
|
priv->timers = t->next;
|
|
if(t->prev != nil)
|
|
panic("timerstate1");
|
|
}
|
|
if(t->next)
|
|
t->next->prev = t->prev;
|
|
if(t->prev)
|
|
t->prev->next = t->next;
|
|
t->next = t->prev = nil;
|
|
}
|
|
} else {
|
|
if(t->state != TcptimerON){
|
|
/* chain */
|
|
if(t->prev != nil || t->next != nil)
|
|
panic("timerstate2");
|
|
t->prev = nil;
|
|
t->next = priv->timers;
|
|
if(t->next)
|
|
t->next->prev = t;
|
|
priv->timers = t;
|
|
}
|
|
}
|
|
t->state = newstate;
|
|
}
|
|
|
|
static void
|
|
tcpackproc(void *a)
|
|
{
|
|
Tcptimer *t, *tp, *timeo;
|
|
Proto *tcp;
|
|
Tcppriv *priv;
|
|
int loop;
|
|
|
|
tcp = a;
|
|
priv = tcp->priv;
|
|
|
|
while(waserror())
|
|
;
|
|
|
|
for(;;) {
|
|
tsleep(&up->sleep, return0, 0, MSPTICK);
|
|
|
|
qlock(&priv->tl);
|
|
timeo = nil;
|
|
loop = 0;
|
|
for(t = priv->timers; t != nil; t = tp) {
|
|
if(loop++ > 10000)
|
|
panic("tcpackproc1");
|
|
tp = t->next;
|
|
if(t->state == TcptimerON) {
|
|
t->count--;
|
|
if(t->count == 0) {
|
|
timerstate(priv, t, TcptimerDONE);
|
|
t->readynext = timeo;
|
|
timeo = t;
|
|
}
|
|
}
|
|
}
|
|
qunlock(&priv->tl);
|
|
|
|
loop = 0;
|
|
for(t = timeo; t != nil; t = t->readynext) {
|
|
if(loop++ > 10000)
|
|
panic("tcpackproc2");
|
|
if(t->state == TcptimerDONE && t->func != nil && !waserror()){
|
|
(*t->func)(t->arg);
|
|
poperror();
|
|
}
|
|
}
|
|
|
|
limborexmit(tcp);
|
|
}
|
|
}
|
|
|
|
static void
|
|
tcpgo(Tcppriv *priv, Tcptimer *t)
|
|
{
|
|
if(t == nil || t->start == 0)
|
|
return;
|
|
|
|
qlock(&priv->tl);
|
|
t->count = t->start;
|
|
timerstate(priv, t, TcptimerON);
|
|
qunlock(&priv->tl);
|
|
}
|
|
|
|
static void
|
|
tcphalt(Tcppriv *priv, Tcptimer *t)
|
|
{
|
|
if(t == nil)
|
|
return;
|
|
|
|
qlock(&priv->tl);
|
|
timerstate(priv, t, TcptimerOFF);
|
|
qunlock(&priv->tl);
|
|
}
|
|
|
|
static int
|
|
backoff(int n)
|
|
{
|
|
return 1 << n;
|
|
}
|
|
|
|
static void
|
|
localclose(Conv *s, char *reason) /* called with c locked */
|
|
{
|
|
Tcpctl *tcb;
|
|
Tcppriv *tpriv;
|
|
|
|
tpriv = s->p->priv;
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
|
|
iphtrem(&tpriv->ht, s);
|
|
|
|
tcphalt(tpriv, &tcb->timer);
|
|
tcphalt(tpriv, &tcb->rtt_timer);
|
|
tcphalt(tpriv, &tcb->acktimer);
|
|
tcphalt(tpriv, &tcb->katimer);
|
|
|
|
/* Flush reassembly queue; nothing more can arrive */
|
|
dumpreseq(tcb);
|
|
|
|
if(tcb->state == Syn_sent)
|
|
Fsconnected(s, reason);
|
|
if(s->state == Announced)
|
|
wakeup(&s->listenr);
|
|
|
|
qhangup(s->rq, reason);
|
|
qhangup(s->wq, reason);
|
|
|
|
tcpsetstate(s, Closed);
|
|
}
|
|
|
|
/* mtu (- TCP + IP hdr len) of 1st hop */
|
|
static int
|
|
tcpmtu(Route *r, int version, uint *scale)
|
|
{
|
|
Ipifc *ifc;
|
|
int mtu;
|
|
|
|
/*
|
|
* set the ws. it doesn't commit us to anything.
|
|
* ws is the ultimate limit to the bandwidth-delay product.
|
|
*/
|
|
*scale = Defadvscale;
|
|
|
|
/*
|
|
* currently we do not implement path MTU discovery
|
|
* so use interface MTU *only* if directly reachable
|
|
* or when we use V4 which allows routers to fragment.
|
|
* otherwise, we use the default MSS which assumes a
|
|
* safe minimum MTU of 1280 bytes for V6.
|
|
*/
|
|
if(r != nil && (ifc = r->ifc) != nil){
|
|
mtu = ifc->maxtu - ifc->m->hsize;
|
|
if(version == V4)
|
|
return mtu - (TCP4_PKT + TCP4_HDRSIZE);
|
|
mtu -= TCP6_PKT + TCP6_HDRSIZE;
|
|
if((r->type & (Rifc|Runi)) != 0 || mtu <= DEF_MSS6)
|
|
return mtu;
|
|
}
|
|
if(version == V6)
|
|
return DEF_MSS6;
|
|
else
|
|
return DEF_MSS;
|
|
}
|
|
|
|
static void
|
|
inittcpctl(Conv *s, int mode)
|
|
{
|
|
Tcpctl *tcb;
|
|
Tcp4hdr* h4;
|
|
Tcp6hdr* h6;
|
|
Tcppriv *tpriv;
|
|
int mss;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
|
|
memset(tcb, 0, sizeof(Tcpctl));
|
|
|
|
tcb->ssthresh = QMAX; /* reset by tcpsetscale() */
|
|
tcb->srtt = tcp_irtt<<LOGAGAIN;
|
|
tcb->mdev = 0;
|
|
|
|
/* setup timers */
|
|
tcb->timer.start = tcp_irtt / MSPTICK;
|
|
tcb->timer.func = tcptimeout;
|
|
tcb->timer.arg = s;
|
|
tcb->rtt_timer.start = MAX_TIME;
|
|
tcb->acktimer.start = TCP_ACK / MSPTICK;
|
|
tcb->acktimer.func = tcpacktimer;
|
|
tcb->acktimer.arg = s;
|
|
tcb->katimer.start = DEF_KAT / MSPTICK;
|
|
tcb->katimer.func = tcpkeepalive;
|
|
tcb->katimer.arg = s;
|
|
|
|
mss = DEF_MSS;
|
|
|
|
/* create a prototype(pseudo) header */
|
|
if(mode != TCP_LISTEN){
|
|
if(ipcmp(s->laddr, IPnoaddr) == 0)
|
|
findlocalip(s->p->f, s->laddr, s->raddr);
|
|
|
|
switch(s->ipversion){
|
|
case V4:
|
|
h4 = &tcb->protohdr.tcp4hdr;
|
|
memset(h4, 0, sizeof(*h4));
|
|
h4->proto = IP_TCPPROTO;
|
|
hnputs(h4->tcpsport, s->lport);
|
|
hnputs(h4->tcpdport, s->rport);
|
|
v6tov4(h4->tcpsrc, s->laddr);
|
|
v6tov4(h4->tcpdst, s->raddr);
|
|
break;
|
|
case V6:
|
|
h6 = &tcb->protohdr.tcp6hdr;
|
|
memset(h6, 0, sizeof(*h6));
|
|
h6->proto = IP_TCPPROTO;
|
|
hnputs(h6->tcpsport, s->lport);
|
|
hnputs(h6->tcpdport, s->rport);
|
|
ipmove(h6->tcpsrc, s->laddr);
|
|
ipmove(h6->tcpdst, s->raddr);
|
|
mss = DEF_MSS6;
|
|
break;
|
|
default:
|
|
panic("inittcpctl: version %d", s->ipversion);
|
|
}
|
|
}
|
|
|
|
tcb->mss = tcb->cwind = mss;
|
|
tcb->abcbytes = 0;
|
|
tpriv = s->p->priv;
|
|
tpriv->stats[Mss] = tcb->mss;
|
|
|
|
/* default is no window scaling */
|
|
tcpsetscale(s, tcb, 0, 0);
|
|
}
|
|
|
|
/*
|
|
* called with s qlocked
|
|
*/
|
|
static void
|
|
tcpstart(Conv *s, int mode)
|
|
{
|
|
Tcpctl *tcb;
|
|
Tcppriv *tpriv;
|
|
char kpname[KNAMELEN];
|
|
|
|
tpriv = s->p->priv;
|
|
|
|
if(tpriv->ackprocstarted == 0){
|
|
qlock(&tpriv->apl);
|
|
if(tpriv->ackprocstarted == 0){
|
|
snprint(kpname, sizeof(kpname), "#I%dtcpack", s->p->f->dev);
|
|
kproc(kpname, tcpackproc, s->p);
|
|
tpriv->ackprocstarted = 1;
|
|
}
|
|
qunlock(&tpriv->apl);
|
|
}
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
|
|
inittcpctl(s, mode);
|
|
|
|
iphtadd(&tpriv->ht, s);
|
|
switch(mode) {
|
|
case TCP_LISTEN:
|
|
tpriv->stats[PassiveOpens]++;
|
|
tcb->flags |= CLONE;
|
|
tcpsetstate(s, Listen);
|
|
break;
|
|
|
|
case TCP_CONNECT:
|
|
tpriv->stats[ActiveOpens]++;
|
|
tcb->flags |= ACTIVE;
|
|
tcpsndsyn(s, tcb);
|
|
tcpsetstate(s, Syn_sent);
|
|
tcpoutput(s);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static char*
|
|
tcpflag(char *buf, char *e, ushort flag)
|
|
{
|
|
char *p;
|
|
|
|
p = seprint(buf, e, "%d", flag>>10); /* Head len */
|
|
if(flag & URG)
|
|
p = seprint(p, e, " URG");
|
|
if(flag & ACK)
|
|
p = seprint(p, e, " ACK");
|
|
if(flag & PSH)
|
|
p = seprint(p, e, " PSH");
|
|
if(flag & RST)
|
|
p = seprint(p, e, " RST");
|
|
if(flag & SYN)
|
|
p = seprint(p, e, " SYN");
|
|
if(flag & FIN)
|
|
p = seprint(p, e, " FIN");
|
|
USED(p);
|
|
return buf;
|
|
}
|
|
|
|
static Block*
|
|
htontcp6(Tcp *tcph, Block *data, Tcp6hdr *ph, Tcpctl *tcb)
|
|
{
|
|
int dlen;
|
|
Tcp6hdr *h;
|
|
ushort csum;
|
|
ushort hdrlen, optpad = 0;
|
|
uchar *opt;
|
|
|
|
hdrlen = TCP6_HDRSIZE;
|
|
if(tcph->flags & SYN){
|
|
if(tcph->mss)
|
|
hdrlen += MSS_LENGTH;
|
|
if(tcph->ws)
|
|
hdrlen += WS_LENGTH;
|
|
optpad = hdrlen & 3;
|
|
if(optpad)
|
|
optpad = 4 - optpad;
|
|
hdrlen += optpad;
|
|
}
|
|
|
|
if(data) {
|
|
dlen = blocklen(data);
|
|
data = padblock(data, hdrlen + TCP6_PKT);
|
|
}
|
|
else {
|
|
dlen = 0;
|
|
data = allocb(hdrlen + TCP6_PKT + 64); /* the 64 pad is to meet mintu's */
|
|
data->wp += hdrlen + TCP6_PKT;
|
|
}
|
|
|
|
/* copy in pseudo ip header plus port numbers */
|
|
h = (Tcp6hdr *)(data->rp);
|
|
memmove(h, ph, TCP6_TCBPHDRSZ);
|
|
|
|
/* compose pseudo tcp header, do cksum calculation */
|
|
hnputl(h->vcf, hdrlen + dlen);
|
|
h->ploadlen[0] = h->ploadlen[1] = h->proto = 0;
|
|
h->ttl = ph->proto;
|
|
|
|
/* copy in variable bits */
|
|
hnputl(h->tcpseq, tcph->seq);
|
|
hnputl(h->tcpack, tcph->ack);
|
|
hnputs(h->tcpflag, (hdrlen<<10) | tcph->flags);
|
|
hnputs(h->tcpwin, tcph->wnd>>(tcb != nil ? tcb->snd.scale : 0));
|
|
hnputs(h->tcpurg, tcph->urg);
|
|
|
|
if(tcph->flags & SYN){
|
|
opt = h->tcpopt;
|
|
if(tcph->mss != 0){
|
|
*opt++ = MSSOPT;
|
|
*opt++ = MSS_LENGTH;
|
|
hnputs(opt, tcph->mss);
|
|
opt += 2;
|
|
}
|
|
if(tcph->ws != 0){
|
|
*opt++ = WSOPT;
|
|
*opt++ = WS_LENGTH;
|
|
*opt++ = tcph->ws;
|
|
}
|
|
while(optpad-- > 0)
|
|
*opt++ = NOOPOPT;
|
|
}
|
|
|
|
if(tcb != nil && tcb->nochecksum){
|
|
h->tcpcksum[0] = h->tcpcksum[1] = 0;
|
|
} else {
|
|
csum = ptclcsum(data, TCP6_IPLEN, hdrlen+dlen+TCP6_PHDRSIZE);
|
|
hnputs(h->tcpcksum, csum);
|
|
}
|
|
|
|
/* move from pseudo header back to normal ip header */
|
|
memset(h->vcf, 0, 4);
|
|
h->vcf[0] = IP_VER6;
|
|
hnputs(h->ploadlen, hdrlen+dlen);
|
|
h->proto = ph->proto;
|
|
|
|
return data;
|
|
}
|
|
|
|
static Block*
|
|
htontcp4(Tcp *tcph, Block *data, Tcp4hdr *ph, Tcpctl *tcb)
|
|
{
|
|
int dlen;
|
|
Tcp4hdr *h;
|
|
ushort csum;
|
|
ushort hdrlen, optpad = 0;
|
|
uchar *opt;
|
|
|
|
hdrlen = TCP4_HDRSIZE;
|
|
if(tcph->flags & SYN){
|
|
if(tcph->mss)
|
|
hdrlen += MSS_LENGTH;
|
|
if(1)
|
|
hdrlen += WS_LENGTH;
|
|
optpad = hdrlen & 3;
|
|
if(optpad)
|
|
optpad = 4 - optpad;
|
|
hdrlen += optpad;
|
|
}
|
|
|
|
if(data) {
|
|
dlen = blocklen(data);
|
|
data = padblock(data, hdrlen + TCP4_PKT);
|
|
}
|
|
else {
|
|
dlen = 0;
|
|
data = allocb(hdrlen + TCP4_PKT + 64); /* the 64 pad is to meet mintu's */
|
|
data->wp += hdrlen + TCP4_PKT;
|
|
}
|
|
|
|
/* copy in pseudo ip header plus port numbers */
|
|
h = (Tcp4hdr *)(data->rp);
|
|
memmove(h, ph, TCP4_TCBPHDRSZ);
|
|
|
|
/* copy in variable bits */
|
|
hnputs(h->tcplen, hdrlen + dlen);
|
|
hnputl(h->tcpseq, tcph->seq);
|
|
hnputl(h->tcpack, tcph->ack);
|
|
hnputs(h->tcpflag, (hdrlen<<10) | tcph->flags);
|
|
hnputs(h->tcpwin, tcph->wnd>>(tcb != nil ? tcb->snd.scale : 0));
|
|
hnputs(h->tcpurg, tcph->urg);
|
|
|
|
if(tcph->flags & SYN){
|
|
opt = h->tcpopt;
|
|
if(tcph->mss != 0){
|
|
*opt++ = MSSOPT;
|
|
*opt++ = MSS_LENGTH;
|
|
hnputs(opt, tcph->mss);
|
|
opt += 2;
|
|
}
|
|
/* always offer. rfc1323 §2.2 */
|
|
if(1){
|
|
*opt++ = WSOPT;
|
|
*opt++ = WS_LENGTH;
|
|
*opt++ = tcph->ws;
|
|
}
|
|
while(optpad-- > 0)
|
|
*opt++ = NOOPOPT;
|
|
}
|
|
|
|
if(tcb != nil && tcb->nochecksum){
|
|
h->tcpcksum[0] = h->tcpcksum[1] = 0;
|
|
} else {
|
|
csum = ptclcsum(data, TCP4_IPLEN, hdrlen+dlen+TCP4_PHDRSIZE);
|
|
hnputs(h->tcpcksum, csum);
|
|
}
|
|
|
|
return data;
|
|
}
|
|
|
|
static int
|
|
ntohtcp6(Tcp *tcph, Block **bpp)
|
|
{
|
|
Tcp6hdr *h;
|
|
uchar *optr;
|
|
ushort hdrlen;
|
|
ushort optlen;
|
|
int n;
|
|
|
|
*bpp = pullupblock(*bpp, TCP6_PKT+TCP6_HDRSIZE);
|
|
if(*bpp == nil)
|
|
return -1;
|
|
|
|
h = (Tcp6hdr *)((*bpp)->rp);
|
|
tcph->source = nhgets(h->tcpsport);
|
|
tcph->dest = nhgets(h->tcpdport);
|
|
tcph->seq = nhgetl(h->tcpseq);
|
|
tcph->ack = nhgetl(h->tcpack);
|
|
hdrlen = (h->tcpflag[0]>>2) & ~3;
|
|
if(hdrlen < TCP6_HDRSIZE) {
|
|
freeblist(*bpp);
|
|
*bpp = nil;
|
|
return -1;
|
|
}
|
|
|
|
tcph->flags = h->tcpflag[1];
|
|
tcph->wnd = nhgets(h->tcpwin);
|
|
tcph->urg = nhgets(h->tcpurg);
|
|
tcph->mss = 0;
|
|
tcph->ws = 0;
|
|
tcph->update = 0;
|
|
tcph->len = nhgets(h->ploadlen) - hdrlen;
|
|
|
|
*bpp = pullupblock(*bpp, hdrlen+TCP6_PKT);
|
|
if(*bpp == nil)
|
|
return -1;
|
|
|
|
optr = h->tcpopt;
|
|
n = hdrlen - TCP6_HDRSIZE;
|
|
while(n > 0 && *optr != EOLOPT) {
|
|
if(*optr == NOOPOPT) {
|
|
n--;
|
|
optr++;
|
|
continue;
|
|
}
|
|
optlen = optr[1];
|
|
if(optlen < 2 || optlen > n)
|
|
break;
|
|
switch(*optr) {
|
|
case MSSOPT:
|
|
if(optlen == MSS_LENGTH)
|
|
tcph->mss = nhgets(optr+2);
|
|
break;
|
|
case WSOPT:
|
|
if(optlen == WS_LENGTH && *(optr+2) <= 14)
|
|
tcph->ws = *(optr+2);
|
|
break;
|
|
}
|
|
n -= optlen;
|
|
optr += optlen;
|
|
}
|
|
return hdrlen;
|
|
}
|
|
|
|
static int
|
|
ntohtcp4(Tcp *tcph, Block **bpp)
|
|
{
|
|
Tcp4hdr *h;
|
|
uchar *optr;
|
|
ushort hdrlen;
|
|
ushort optlen;
|
|
int n;
|
|
|
|
*bpp = pullupblock(*bpp, TCP4_PKT+TCP4_HDRSIZE);
|
|
if(*bpp == nil)
|
|
return -1;
|
|
|
|
h = (Tcp4hdr *)((*bpp)->rp);
|
|
tcph->source = nhgets(h->tcpsport);
|
|
tcph->dest = nhgets(h->tcpdport);
|
|
tcph->seq = nhgetl(h->tcpseq);
|
|
tcph->ack = nhgetl(h->tcpack);
|
|
|
|
hdrlen = (h->tcpflag[0]>>2) & ~3;
|
|
if(hdrlen < TCP4_HDRSIZE) {
|
|
freeblist(*bpp);
|
|
*bpp = nil;
|
|
return -1;
|
|
}
|
|
|
|
tcph->flags = h->tcpflag[1];
|
|
tcph->wnd = nhgets(h->tcpwin);
|
|
tcph->urg = nhgets(h->tcpurg);
|
|
tcph->mss = 0;
|
|
tcph->ws = 0;
|
|
tcph->update = 0;
|
|
tcph->len = nhgets(h->length) - (hdrlen + TCP4_PKT);
|
|
|
|
*bpp = pullupblock(*bpp, hdrlen+TCP4_PKT);
|
|
if(*bpp == nil)
|
|
return -1;
|
|
|
|
optr = h->tcpopt;
|
|
n = hdrlen - TCP4_HDRSIZE;
|
|
while(n > 0 && *optr != EOLOPT) {
|
|
if(*optr == NOOPOPT) {
|
|
n--;
|
|
optr++;
|
|
continue;
|
|
}
|
|
optlen = optr[1];
|
|
if(optlen < 2 || optlen > n)
|
|
break;
|
|
switch(*optr) {
|
|
case MSSOPT:
|
|
if(optlen == MSS_LENGTH)
|
|
tcph->mss = nhgets(optr+2);
|
|
break;
|
|
case WSOPT:
|
|
if(optlen == WS_LENGTH && *(optr+2) <= 14)
|
|
tcph->ws = *(optr+2);
|
|
break;
|
|
}
|
|
n -= optlen;
|
|
optr += optlen;
|
|
}
|
|
return hdrlen;
|
|
}
|
|
|
|
/*
|
|
* For outgoing calls, generate an initial sequence
|
|
* number and put a SYN on the send queue
|
|
*/
|
|
static void
|
|
tcpsndsyn(Conv *s, Tcpctl *tcb)
|
|
{
|
|
Tcppriv *tpriv;
|
|
|
|
tcb->iss = (nrand(1<<16)<<16)|nrand(1<<16);
|
|
tcb->rttseq = tcb->iss;
|
|
tcb->snd.wl2 = tcb->iss;
|
|
tcb->snd.una = tcb->iss;
|
|
tcb->snd.rxt = tcb->iss;
|
|
tcb->snd.ptr = tcb->rttseq;
|
|
tcb->snd.nxt = tcb->rttseq;
|
|
tcb->flgcnt++;
|
|
tcb->flags |= FORCE;
|
|
tcb->sndsyntime = NOW;
|
|
|
|
/* set desired mss and scale */
|
|
tcb->mss = tcpmtu(v6lookup(s->p->f, s->raddr, s->laddr, s), s->ipversion, &tcb->scale);
|
|
tpriv = s->p->priv;
|
|
tpriv->stats[Mss] = tcb->mss;
|
|
}
|
|
|
|
static int
|
|
sndrst(Proto *tcp, uchar *source, uchar *dest, ushort length, Tcp *seg, uchar version, char *reason, Routehint *rh)
|
|
{
|
|
Block *hbp;
|
|
uchar rflags;
|
|
Tcppriv *tpriv;
|
|
Tcp4hdr ph4;
|
|
Tcp6hdr ph6;
|
|
|
|
netlog(tcp->f, Logtcp, "sndrst: %s\n", reason);
|
|
|
|
tpriv = tcp->priv;
|
|
|
|
if(seg->flags & RST)
|
|
return -1;
|
|
|
|
/* make pseudo header */
|
|
switch(version) {
|
|
case V4:
|
|
memset(&ph4, 0, sizeof(ph4));
|
|
ph4.vihl = IP_VER4;
|
|
v6tov4(ph4.tcpsrc, dest);
|
|
v6tov4(ph4.tcpdst, source);
|
|
ph4.proto = IP_TCPPROTO;
|
|
hnputs(ph4.tcplen, TCP4_HDRSIZE);
|
|
hnputs(ph4.tcpsport, seg->dest);
|
|
hnputs(ph4.tcpdport, seg->source);
|
|
break;
|
|
case V6:
|
|
memset(&ph6, 0, sizeof(ph6));
|
|
ph6.vcf[0] = IP_VER6;
|
|
ipmove(ph6.tcpsrc, dest);
|
|
ipmove(ph6.tcpdst, source);
|
|
ph6.proto = IP_TCPPROTO;
|
|
hnputs(ph6.ploadlen, TCP6_HDRSIZE);
|
|
hnputs(ph6.tcpsport, seg->dest);
|
|
hnputs(ph6.tcpdport, seg->source);
|
|
break;
|
|
default:
|
|
panic("sndrst: version %d", version);
|
|
}
|
|
|
|
tpriv->stats[OutRsts]++;
|
|
rflags = RST;
|
|
|
|
/* convince the other end that this reset is in band */
|
|
if(seg->flags & ACK) {
|
|
seg->seq = seg->ack;
|
|
seg->ack = 0;
|
|
}
|
|
else {
|
|
rflags |= ACK;
|
|
seg->ack = seg->seq;
|
|
seg->seq = 0;
|
|
if(seg->flags & SYN)
|
|
seg->ack++;
|
|
seg->ack += length;
|
|
if(seg->flags & FIN)
|
|
seg->ack++;
|
|
}
|
|
seg->flags = rflags;
|
|
seg->wnd = 0;
|
|
seg->urg = 0;
|
|
seg->mss = 0;
|
|
seg->ws = 0;
|
|
switch(version) {
|
|
case V4:
|
|
hbp = htontcp4(seg, nil, &ph4, nil);
|
|
return ipoput4(tcp->f, hbp, 0, MAXTTL, DFLTTOS, rh);
|
|
case V6:
|
|
hbp = htontcp6(seg, nil, &ph6, nil);
|
|
return ipoput6(tcp->f, hbp, 0, MAXTTL, DFLTTOS, rh);
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* send a reset to the remote side and close the conversation
|
|
* called with s qlocked
|
|
*/
|
|
static char*
|
|
tcphangup(Conv *s)
|
|
{
|
|
Tcp seg;
|
|
Tcpctl *tcb;
|
|
Block *hbp;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
if(waserror())
|
|
return commonerror();
|
|
if(ipcmp(s->raddr, IPnoaddr) != 0) {
|
|
if(!waserror()){
|
|
memset(&seg, 0, sizeof seg);
|
|
seg.flags = RST | ACK;
|
|
seg.ack = tcb->rcv.nxt;
|
|
tcb->rcv.ackptr = seg.ack;
|
|
seg.seq = tcb->snd.ptr;
|
|
seg.wnd = 0;
|
|
seg.urg = 0;
|
|
seg.mss = 0;
|
|
seg.ws = 0;
|
|
switch(s->ipversion) {
|
|
case V4:
|
|
tcb->protohdr.tcp4hdr.vihl = IP_VER4;
|
|
hbp = htontcp4(&seg, nil, &tcb->protohdr.tcp4hdr, tcb);
|
|
ipoput4(s->p->f, hbp, 0, s->ttl, s->tos, s);
|
|
break;
|
|
case V6:
|
|
tcb->protohdr.tcp6hdr.vcf[0] = IP_VER6;
|
|
hbp = htontcp6(&seg, nil, &tcb->protohdr.tcp6hdr, tcb);
|
|
ipoput6(s->p->f, hbp, 0, s->ttl, s->tos, s);
|
|
break;
|
|
default:
|
|
panic("tcphangup: version %d", s->ipversion);
|
|
}
|
|
poperror();
|
|
}
|
|
}
|
|
localclose(s, nil);
|
|
poperror();
|
|
return nil;
|
|
}
|
|
|
|
/*
|
|
* (re)send a SYN ACK
|
|
*/
|
|
static int
|
|
sndsynack(Proto *tcp, Limbo *lp)
|
|
{
|
|
Routehint rh;
|
|
Route *rt;
|
|
Block *hbp;
|
|
Tcp4hdr ph4;
|
|
Tcp6hdr ph6;
|
|
Tcp seg;
|
|
uint scale;
|
|
|
|
rh.r = nil;
|
|
rh.a = nil;
|
|
if((rt = v6lookup(tcp->f, lp->raddr, lp->laddr, &rh)) == nil)
|
|
return -1;
|
|
|
|
/* make pseudo header */
|
|
switch(lp->version) {
|
|
case V4:
|
|
memset(&ph4, 0, sizeof(ph4));
|
|
ph4.vihl = IP_VER4;
|
|
v6tov4(ph4.tcpsrc, lp->laddr);
|
|
v6tov4(ph4.tcpdst, lp->raddr);
|
|
ph4.proto = IP_TCPPROTO;
|
|
hnputs(ph4.tcplen, TCP4_HDRSIZE);
|
|
hnputs(ph4.tcpsport, lp->lport);
|
|
hnputs(ph4.tcpdport, lp->rport);
|
|
break;
|
|
case V6:
|
|
memset(&ph6, 0, sizeof(ph6));
|
|
ph6.vcf[0] = IP_VER6;
|
|
ipmove(ph6.tcpsrc, lp->laddr);
|
|
ipmove(ph6.tcpdst, lp->raddr);
|
|
ph6.proto = IP_TCPPROTO;
|
|
hnputs(ph6.ploadlen, TCP6_HDRSIZE);
|
|
hnputs(ph6.tcpsport, lp->lport);
|
|
hnputs(ph6.tcpdport, lp->rport);
|
|
break;
|
|
default:
|
|
panic("sndsynack: version %d", lp->version);
|
|
}
|
|
|
|
memset(&seg, 0, sizeof seg);
|
|
seg.seq = lp->iss;
|
|
seg.ack = lp->irs+1;
|
|
seg.flags = SYN|ACK;
|
|
seg.urg = 0;
|
|
seg.mss = tcpmtu(rt, lp->version, &scale);
|
|
seg.wnd = QMAX;
|
|
|
|
/* if the other side set scale, we should too */
|
|
if(lp->rcvscale){
|
|
seg.ws = scale;
|
|
lp->sndscale = scale;
|
|
} else {
|
|
seg.ws = 0;
|
|
lp->sndscale = 0;
|
|
}
|
|
lp->lastsend = NOW;
|
|
|
|
switch(lp->version) {
|
|
case V4:
|
|
hbp = htontcp4(&seg, nil, &ph4, nil);
|
|
return ipoput4(tcp->f, hbp, 0, MAXTTL, DFLTTOS, &rh);
|
|
case V6:
|
|
hbp = htontcp6(&seg, nil, &ph6, nil);
|
|
return ipoput6(tcp->f, hbp, 0, MAXTTL, DFLTTOS, &rh);
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
#define hashipa(a, p) ( ( (a)[IPaddrlen-2] + (a)[IPaddrlen-1] + p )&LHTMASK )
|
|
|
|
/*
|
|
* put a call into limbo and respond with a SYN ACK
|
|
*
|
|
* called with proto locked
|
|
*/
|
|
static void
|
|
limbo(Conv *s, uchar *source, uchar *dest, Tcp *seg, int version)
|
|
{
|
|
Limbo *lp, **l;
|
|
Tcppriv *tpriv;
|
|
int h;
|
|
|
|
tpriv = s->p->priv;
|
|
h = hashipa(source, seg->source);
|
|
|
|
for(l = &tpriv->lht[h]; *l != nil; l = &lp->next){
|
|
lp = *l;
|
|
if(lp->lport != seg->dest || lp->rport != seg->source || lp->version != version)
|
|
continue;
|
|
if(ipcmp(lp->raddr, source) != 0)
|
|
continue;
|
|
if(ipcmp(lp->laddr, dest) != 0)
|
|
continue;
|
|
|
|
/* each new SYN restarts the retransmits */
|
|
lp->irs = seg->seq;
|
|
break;
|
|
}
|
|
lp = *l;
|
|
if(lp == nil){
|
|
if(tpriv->nlimbo >= Maxlimbo && tpriv->lht[h]){
|
|
lp = tpriv->lht[h];
|
|
tpriv->lht[h] = lp->next;
|
|
lp->next = nil;
|
|
} else {
|
|
lp = malloc(sizeof(*lp));
|
|
if(lp == nil)
|
|
return;
|
|
tpriv->nlimbo++;
|
|
}
|
|
*l = lp;
|
|
lp->version = version;
|
|
ipmove(lp->laddr, dest);
|
|
ipmove(lp->raddr, source);
|
|
lp->lport = seg->dest;
|
|
lp->rport = seg->source;
|
|
lp->mss = seg->mss;
|
|
lp->rcvscale = seg->ws;
|
|
lp->irs = seg->seq;
|
|
lp->iss = (nrand(1<<16)<<16)|nrand(1<<16);
|
|
}
|
|
|
|
if(sndsynack(s->p, lp) < 0){
|
|
*l = lp->next;
|
|
tpriv->nlimbo--;
|
|
free(lp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* resend SYN ACK's once every SYNACK_RXTIMER ms.
|
|
*/
|
|
static void
|
|
limborexmit(Proto *tcp)
|
|
{
|
|
Tcppriv *tpriv;
|
|
Limbo **l, *lp;
|
|
int h;
|
|
int seen;
|
|
ulong now;
|
|
|
|
tpriv = tcp->priv;
|
|
|
|
if(!canqlock(tcp))
|
|
return;
|
|
if(waserror()){
|
|
qunlock(tcp);
|
|
return;
|
|
}
|
|
seen = 0;
|
|
now = NOW;
|
|
for(h = 0; h < NLHT && seen < tpriv->nlimbo; h++){
|
|
for(l = &tpriv->lht[h]; *l != nil && seen < tpriv->nlimbo; ){
|
|
lp = *l;
|
|
seen++;
|
|
if(now - lp->lastsend < (lp->rexmits+1)*SYNACK_RXTIMER)
|
|
continue;
|
|
|
|
/* time it out after 1 second */
|
|
if(++(lp->rexmits) > 5){
|
|
tpriv->nlimbo--;
|
|
*l = lp->next;
|
|
free(lp);
|
|
continue;
|
|
}
|
|
|
|
/* if we're being attacked, don't bother resending SYN ACK's */
|
|
if(tpriv->nlimbo > 100)
|
|
continue;
|
|
|
|
if(sndsynack(tcp, lp) < 0){
|
|
*l = lp->next;
|
|
tpriv->nlimbo--;
|
|
free(lp);
|
|
continue;
|
|
}
|
|
|
|
l = &lp->next;
|
|
}
|
|
}
|
|
qunlock(tcp);
|
|
poperror();
|
|
}
|
|
|
|
/*
|
|
* lookup call in limbo. if found, throw it out.
|
|
*
|
|
* called with proto locked
|
|
*/
|
|
static void
|
|
limborst(Conv *s, Tcp *segp, uchar *src, uchar *dst, uchar version)
|
|
{
|
|
Limbo *lp, **l;
|
|
int h;
|
|
Tcppriv *tpriv;
|
|
|
|
tpriv = s->p->priv;
|
|
|
|
/* find a call in limbo */
|
|
h = hashipa(src, segp->source);
|
|
for(l = &tpriv->lht[h]; *l != nil; l = &lp->next){
|
|
lp = *l;
|
|
if(lp->lport != segp->dest || lp->rport != segp->source || lp->version != version)
|
|
continue;
|
|
if(ipcmp(lp->laddr, dst) != 0)
|
|
continue;
|
|
if(ipcmp(lp->raddr, src) != 0)
|
|
continue;
|
|
|
|
/* RST can only follow the SYN */
|
|
if(segp->seq == lp->irs+1){
|
|
tpriv->nlimbo--;
|
|
*l = lp->next;
|
|
free(lp);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void
|
|
initialwindow(Tcpctl *tcb)
|
|
{
|
|
/* RFC 3390 initial window */
|
|
if(tcb->mss < 1095)
|
|
tcb->cwind = 4*tcb->mss;
|
|
else if(tcb->mss < 2190)
|
|
tcb->cwind = 4380;
|
|
else
|
|
tcb->cwind = 2*tcb->mss;
|
|
}
|
|
|
|
/*
|
|
* come here when we finally get an ACK to our SYN-ACK.
|
|
* lookup call in limbo. if found, create a new conversation
|
|
*
|
|
* called with proto locked
|
|
*/
|
|
static Conv*
|
|
tcpincoming(Conv *s, Tcp *segp, uchar *src, uchar *dst, uchar version)
|
|
{
|
|
Conv *new;
|
|
Tcpctl *tcb;
|
|
Tcppriv *tpriv;
|
|
Tcp4hdr *h4;
|
|
Tcp6hdr *h6;
|
|
Limbo *lp, **l;
|
|
int h;
|
|
|
|
/* unless it's just an ack, it can't be someone coming out of limbo */
|
|
if((segp->flags & SYN) || (segp->flags & ACK) == 0)
|
|
return nil;
|
|
|
|
tpriv = s->p->priv;
|
|
|
|
/* find a call in limbo */
|
|
h = hashipa(src, segp->source);
|
|
for(l = &tpriv->lht[h]; (lp = *l) != nil; l = &lp->next){
|
|
netlog(s->p->f, Logtcp, "tcpincoming s %I!%ud/%I!%ud d %I!%ud/%I!%ud v %d/%d\n",
|
|
src, segp->source, lp->raddr, lp->rport,
|
|
dst, segp->dest, lp->laddr, lp->lport,
|
|
version, lp->version
|
|
);
|
|
|
|
if(lp->lport != segp->dest || lp->rport != segp->source || lp->version != version)
|
|
continue;
|
|
if(ipcmp(lp->laddr, dst) != 0)
|
|
continue;
|
|
if(ipcmp(lp->raddr, src) != 0)
|
|
continue;
|
|
|
|
/* we're assuming no data with the initial SYN */
|
|
if(segp->seq != lp->irs+1 || segp->ack != lp->iss+1){
|
|
netlog(s->p->f, Logtcp, "tcpincoming s %lux/%lux a %lux %lux\n",
|
|
segp->seq, lp->irs+1, segp->ack, lp->iss+1);
|
|
lp = nil;
|
|
} else {
|
|
tpriv->nlimbo--;
|
|
*l = lp->next;
|
|
}
|
|
break;
|
|
}
|
|
if(lp == nil)
|
|
return nil;
|
|
|
|
new = Fsnewcall(s, src, segp->source, dst, segp->dest, version);
|
|
if(new == nil)
|
|
return nil;
|
|
|
|
memmove(new->ptcl, s->ptcl, sizeof(Tcpctl));
|
|
tcb = (Tcpctl*)new->ptcl;
|
|
tcb->flags &= ~CLONE;
|
|
tcb->timer.arg = new;
|
|
tcb->timer.state = TcptimerOFF;
|
|
tcb->acktimer.arg = new;
|
|
tcb->acktimer.state = TcptimerOFF;
|
|
tcb->katimer.arg = new;
|
|
tcb->katimer.state = TcptimerOFF;
|
|
tcb->rtt_timer.arg = new;
|
|
tcb->rtt_timer.state = TcptimerOFF;
|
|
|
|
tcb->irs = lp->irs;
|
|
tcb->rcv.nxt = tcb->irs+1;
|
|
tcb->rcv.wptr = tcb->rcv.nxt;
|
|
tcb->rcv.wsnt = 0;
|
|
tcb->rcv.urg = tcb->rcv.nxt;
|
|
|
|
tcb->iss = lp->iss;
|
|
tcb->rttseq = tcb->iss;
|
|
tcb->snd.wl2 = tcb->iss;
|
|
tcb->snd.una = tcb->iss+1;
|
|
tcb->snd.ptr = tcb->iss+1;
|
|
tcb->snd.nxt = tcb->iss+1;
|
|
tcb->snd.rxt = tcb->iss+1;
|
|
tcb->flgcnt = 0;
|
|
tcb->flags |= SYNACK;
|
|
|
|
/* set desired mss and scale */
|
|
tcb->mss = tcpmtu(v6lookup(s->p->f, src, dst, s), version, &tcb->scale);
|
|
|
|
/* our sending max segment size cannot be bigger than what he asked for */
|
|
if(lp->mss != 0 && lp->mss < tcb->mss)
|
|
tcb->mss = lp->mss;
|
|
tpriv->stats[Mss] = tcb->mss;
|
|
|
|
/* window scaling */
|
|
tcpsetscale(new, tcb, lp->rcvscale, lp->sndscale);
|
|
|
|
/* congestion window */
|
|
tcb->snd.wnd = segp->wnd;
|
|
initialwindow(tcb);
|
|
|
|
/* set initial round trip time */
|
|
tcb->sndsyntime = lp->lastsend+lp->rexmits*SYNACK_RXTIMER;
|
|
tcpsynackrtt(new);
|
|
|
|
free(lp);
|
|
|
|
/* set up proto header */
|
|
switch(version){
|
|
case V4:
|
|
h4 = &tcb->protohdr.tcp4hdr;
|
|
memset(h4, 0, sizeof(*h4));
|
|
h4->proto = IP_TCPPROTO;
|
|
hnputs(h4->tcpsport, new->lport);
|
|
hnputs(h4->tcpdport, new->rport);
|
|
v6tov4(h4->tcpsrc, dst);
|
|
v6tov4(h4->tcpdst, src);
|
|
break;
|
|
case V6:
|
|
h6 = &tcb->protohdr.tcp6hdr;
|
|
memset(h6, 0, sizeof(*h6));
|
|
h6->proto = IP_TCPPROTO;
|
|
hnputs(h6->tcpsport, new->lport);
|
|
hnputs(h6->tcpdport, new->rport);
|
|
ipmove(h6->tcpsrc, dst);
|
|
ipmove(h6->tcpdst, src);
|
|
break;
|
|
default:
|
|
panic("tcpincoming: version %d", new->ipversion);
|
|
}
|
|
|
|
tcpsetstate(new, Established);
|
|
iphtadd(&tpriv->ht, new);
|
|
return new;
|
|
}
|
|
|
|
static int
|
|
seq_within(ulong x, ulong low, ulong high)
|
|
{
|
|
if(low <= high){
|
|
if(low <= x && x <= high)
|
|
return 1;
|
|
}
|
|
else {
|
|
if(x >= low || x <= high)
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
seq_lt(ulong x, ulong y)
|
|
{
|
|
return (int)(x-y) < 0;
|
|
}
|
|
|
|
static int
|
|
seq_le(ulong x, ulong y)
|
|
{
|
|
return (int)(x-y) <= 0;
|
|
}
|
|
|
|
static int
|
|
seq_gt(ulong x, ulong y)
|
|
{
|
|
return (int)(x-y) > 0;
|
|
}
|
|
|
|
static int
|
|
seq_ge(ulong x, ulong y)
|
|
{
|
|
return (int)(x-y) >= 0;
|
|
}
|
|
|
|
/*
|
|
* use the time between the first SYN and it's ack as the
|
|
* initial round trip time
|
|
*/
|
|
static void
|
|
tcpsynackrtt(Conv *s)
|
|
{
|
|
Tcpctl *tcb;
|
|
int delta;
|
|
Tcppriv *tpriv;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
tpriv = s->p->priv;
|
|
|
|
delta = NOW - tcb->sndsyntime;
|
|
tcb->srtt = delta<<LOGAGAIN;
|
|
tcb->mdev = delta<<LOGDGAIN;
|
|
|
|
/* halt round trip timer */
|
|
tcphalt(tpriv, &tcb->rtt_timer);
|
|
}
|
|
|
|
static void
|
|
update(Conv *s, Tcp *seg)
|
|
{
|
|
int rtt, delta;
|
|
Tcpctl *tcb;
|
|
ulong acked;
|
|
Tcppriv *tpriv;
|
|
|
|
if(seg->update)
|
|
return;
|
|
seg->update = 1;
|
|
|
|
tpriv = s->p->priv;
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
|
|
/* catch zero-window updates, update window & recover */
|
|
if(tcb->snd.wnd == 0 && seg->wnd > 0)
|
|
if(seq_lt(seg->ack, tcb->snd.ptr)){
|
|
netlog(s->p->f, Logtcp, "tcp: zwu ack %lud una %lud ptr %lud win %lud\n",
|
|
seg->ack, tcb->snd.una, tcb->snd.ptr, seg->wnd);
|
|
tcb->snd.wnd = seg->wnd;
|
|
goto recovery;
|
|
}
|
|
|
|
/* newreno fast retransmit */
|
|
if(seg->ack == tcb->snd.una)
|
|
if(tcb->snd.una != tcb->snd.nxt)
|
|
if(++tcb->snd.dupacks == 3){
|
|
recovery:
|
|
if(tcb->snd.recovery){
|
|
tpriv->stats[RecoveryCwind]++;
|
|
tcb->cwind += tcb->mss;
|
|
}else if(seq_le(tcb->snd.rxt, seg->ack)){
|
|
tpriv->stats[Recovery]++;
|
|
tcb->abcbytes = 0;
|
|
tcb->snd.recovery = 1;
|
|
tcb->snd.partialack = 0;
|
|
tcb->snd.rxt = tcb->snd.nxt;
|
|
tcpcongestion(tcb);
|
|
tcb->cwind = tcb->ssthresh + 3*tcb->mss;
|
|
netlog(s->p->f, Logtcpwin, "recovery inflate %ld ss %ld @%lud\n",
|
|
tcb->cwind, tcb->ssthresh, tcb->snd.rxt);
|
|
tcprxmit(s);
|
|
}else{
|
|
tpriv->stats[RecoveryNoSeq]++;
|
|
netlog(s->p->f, Logtcpwin, "!recov %lud not ≤ %lud %ld\n",
|
|
tcb->snd.rxt, seg->ack, tcb->snd.rxt - seg->ack);
|
|
/* do not enter fast retransmit */
|
|
/* do not change ssthresh */
|
|
}
|
|
}else if(tcb->snd.recovery){
|
|
tpriv->stats[RecoveryCwind]++;
|
|
tcb->cwind += tcb->mss;
|
|
}
|
|
|
|
/*
|
|
* update window
|
|
*/
|
|
if(seq_gt(seg->ack, tcb->snd.wl2)
|
|
|| (tcb->snd.wl2 == seg->ack && seg->wnd > tcb->snd.wnd)){
|
|
/* clear dupack if we advance wl2 */
|
|
if(tcb->snd.wl2 != seg->ack)
|
|
tcb->snd.dupacks = 0;
|
|
tcb->snd.wnd = seg->wnd;
|
|
tcb->snd.wl2 = seg->ack;
|
|
}
|
|
|
|
if(!seq_gt(seg->ack, tcb->snd.una)){
|
|
/*
|
|
* don't let us hangup if sending into a closed window and
|
|
* we're still getting acks
|
|
*/
|
|
if((tcb->flags&RETRAN) && tcb->snd.wnd == 0)
|
|
tcb->backedoff = MAXBACKMS/4;
|
|
return;
|
|
}
|
|
|
|
/* Compute the new send window size */
|
|
acked = seg->ack - tcb->snd.una;
|
|
|
|
/* avoid slow start and timers for SYN acks */
|
|
if((tcb->flags & SYNACK) == 0) {
|
|
tcb->flags |= SYNACK;
|
|
acked--;
|
|
tcb->flgcnt--;
|
|
goto done;
|
|
}
|
|
|
|
/*
|
|
* congestion control
|
|
*/
|
|
if(tcb->snd.recovery){
|
|
if(seq_ge(seg->ack, tcb->snd.rxt)){
|
|
/* recovery finished; deflate window */
|
|
tpriv->stats[RecoveryDone]++;
|
|
tcb->snd.dupacks = 0;
|
|
tcb->snd.recovery = 0;
|
|
tcb->cwind = (tcb->snd.nxt - tcb->snd.una) + tcb->mss;
|
|
if(tcb->ssthresh < tcb->cwind)
|
|
tcb->cwind = tcb->ssthresh;
|
|
netlog(s->p->f, Logtcpwin, "recovery deflate %ld %ld\n",
|
|
tcb->cwind, tcb->ssthresh);
|
|
} else {
|
|
/* partial ack; we lost more than one segment */
|
|
tpriv->stats[RecoveryPA]++;
|
|
if(tcb->cwind > acked)
|
|
tcb->cwind -= acked;
|
|
else{
|
|
netlog(s->p->f, Logtcpwin, "partial ack neg\n");
|
|
tcb->cwind = tcb->mss;
|
|
}
|
|
netlog(s->p->f, Logtcpwin, "partial ack %ld left %ld cwind %ld\n",
|
|
acked, tcb->snd.rxt - seg->ack, tcb->cwind);
|
|
|
|
if(acked >= tcb->mss)
|
|
tcb->cwind += tcb->mss;
|
|
tcb->snd.partialack++;
|
|
}
|
|
} else
|
|
tcpabcincr(tcb, acked);
|
|
|
|
/* Adjust the timers according to the round trip time */
|
|
/* todo: fix sloppy treatment of overflow cases here. */
|
|
if(tcb->rtt_timer.state == TcptimerON && seq_ge(seg->ack, tcb->rttseq)) {
|
|
tcphalt(tpriv, &tcb->rtt_timer);
|
|
if((tcb->flags&RETRAN) == 0) {
|
|
tcb->backoff = 0;
|
|
tcb->backedoff = 0;
|
|
rtt = tcb->rtt_timer.start - tcb->rtt_timer.count;
|
|
if(rtt == 0)
|
|
rtt = 1; /* otherwise all close systems will rexmit in 0 time */
|
|
rtt *= MSPTICK;
|
|
if(tcb->srtt == 0) {
|
|
tcb->srtt = rtt << LOGAGAIN;
|
|
tcb->mdev = rtt << LOGDGAIN;
|
|
} else {
|
|
delta = rtt - (tcb->srtt>>LOGAGAIN);
|
|
tcb->srtt += delta;
|
|
if(tcb->srtt <= 0)
|
|
tcb->srtt = 1;
|
|
|
|
delta = abs(delta) - (tcb->mdev>>LOGDGAIN);
|
|
tcb->mdev += delta;
|
|
if(tcb->mdev <= 0)
|
|
tcb->mdev = 1;
|
|
}
|
|
tcpsettimer(tcb);
|
|
}
|
|
}
|
|
|
|
done:
|
|
if(qdiscard(s->wq, acked) < acked)
|
|
tcb->flgcnt--;
|
|
tcb->snd.una = seg->ack;
|
|
|
|
/* newreno fast recovery */
|
|
if(tcb->snd.recovery)
|
|
tcprxmit(s);
|
|
|
|
if(seq_gt(seg->ack, tcb->snd.urg))
|
|
tcb->snd.urg = seg->ack;
|
|
|
|
if(tcb->snd.una != tcb->snd.nxt){
|
|
/* “impatient” variant */
|
|
if(!tcb->snd.recovery || tcb->snd.partialack == 1){
|
|
tcb->time = NOW;
|
|
tcb->timeuna = tcb->snd.una;
|
|
tcpgo(tpriv, &tcb->timer);
|
|
}
|
|
}
|
|
else
|
|
tcphalt(tpriv, &tcb->timer);
|
|
|
|
if(seq_lt(tcb->snd.ptr, tcb->snd.una))
|
|
tcb->snd.ptr = tcb->snd.una;
|
|
|
|
if(!tcb->snd.recovery)
|
|
tcb->flags &= ~RETRAN;
|
|
tcb->backoff = 0;
|
|
tcb->backedoff = 0;
|
|
}
|
|
|
|
static void
|
|
tcpiput(Proto *tcp, Ipifc*, Block *bp)
|
|
{
|
|
Tcp seg;
|
|
Tcp4hdr *h4;
|
|
Tcp6hdr *h6;
|
|
Tcpctl *tcb;
|
|
int hdrlen;
|
|
ushort length;
|
|
uchar source[IPaddrlen], dest[IPaddrlen];
|
|
Iphash *iph;
|
|
Conv *s;
|
|
Fs *f;
|
|
Tcppriv *tpriv;
|
|
char *reason;
|
|
uchar version;
|
|
|
|
f = tcp->f;
|
|
tpriv = tcp->priv;
|
|
|
|
tpriv->stats[InSegs]++;
|
|
|
|
h4 = (Tcp4hdr*)(bp->rp);
|
|
h6 = (Tcp6hdr*)(bp->rp);
|
|
|
|
if((h4->vihl&0xF0)==IP_VER4) {
|
|
int ttl = h4->ttl;
|
|
|
|
version = V4;
|
|
length = nhgets(h4->length);
|
|
if(length < TCP4_PKT){
|
|
tpriv->stats[HlenErrs]++;
|
|
tpriv->stats[InErrs]++;
|
|
netlog(f, Logtcp, "bad tcp len\n");
|
|
freeblist(bp);
|
|
return;
|
|
}
|
|
length -= TCP4_PKT;
|
|
v4tov6(dest, h4->tcpdst);
|
|
v4tov6(source, h4->tcpsrc);
|
|
|
|
h4->ttl = 0;
|
|
hnputs(h4->tcplen, length);
|
|
if(!(bp->flag & Btcpck) && (h4->tcpcksum[0] || h4->tcpcksum[1])
|
|
&& ptclcsum(bp, TCP4_IPLEN, length + TCP4_PKT - TCP4_IPLEN)) {
|
|
tpriv->stats[CsumErrs]++;
|
|
tpriv->stats[InErrs]++;
|
|
netlog(f, Logtcp, "bad tcp proto cksum\n");
|
|
freeblist(bp);
|
|
return;
|
|
}
|
|
h4->ttl = ttl;
|
|
|
|
hdrlen = ntohtcp4(&seg, &bp);
|
|
if(hdrlen < 0){
|
|
tpriv->stats[HlenErrs]++;
|
|
tpriv->stats[InErrs]++;
|
|
netlog(f, Logtcp, "bad tcp hdr len\n");
|
|
return;
|
|
}
|
|
length -= hdrlen;
|
|
hdrlen += TCP4_PKT;
|
|
}
|
|
else {
|
|
int ttl = h6->ttl;
|
|
int proto = h6->proto;
|
|
|
|
version = V6;
|
|
length = nhgets(h6->ploadlen);
|
|
ipmove(dest, h6->tcpdst);
|
|
ipmove(source, h6->tcpsrc);
|
|
|
|
h6->ploadlen[0] = h6->ploadlen[1] = h6->proto = 0;
|
|
h6->ttl = proto;
|
|
hnputl(h6->vcf, length);
|
|
if((h6->tcpcksum[0] || h6->tcpcksum[1])
|
|
&& ptclcsum(bp, TCP6_IPLEN, length+TCP6_PHDRSIZE) != 0) {
|
|
tpriv->stats[CsumErrs]++;
|
|
tpriv->stats[InErrs]++;
|
|
netlog(f, Logtcp,
|
|
"bad tcpv6 proto cksum: got %#ux\n",
|
|
h6->tcpcksum[0]<<8 | h6->tcpcksum[1]);
|
|
freeblist(bp);
|
|
return;
|
|
}
|
|
h6->ttl = ttl;
|
|
h6->proto = proto;
|
|
hnputs(h6->ploadlen, length);
|
|
|
|
hdrlen = ntohtcp6(&seg, &bp);
|
|
if(hdrlen < 0){
|
|
tpriv->stats[HlenErrs]++;
|
|
tpriv->stats[InErrs]++;
|
|
netlog(f, Logtcp, "bad tcpv6 hdr len\n");
|
|
return;
|
|
}
|
|
length -= hdrlen;
|
|
hdrlen += TCP6_PKT;
|
|
}
|
|
|
|
/* lock protocol while searching for a conversation */
|
|
qlock(tcp);
|
|
|
|
/* Look for a matching conversation */
|
|
iph = iphtlook(&tpriv->ht, source, seg.source, dest, seg.dest);
|
|
if(iph == nil){
|
|
netlog(f, Logtcp, "iphtlook(src %I!%d, dst %I!%d) failed\n",
|
|
source, seg.source, dest, seg.dest);
|
|
reset:
|
|
qunlock(tcp);
|
|
freeblist(bp);
|
|
sndrst(tcp, source, dest, length, &seg, version, "no conversation", nil);
|
|
return;
|
|
}
|
|
if(iph->trans){
|
|
Translation *q;
|
|
int hop = h4->ttl;
|
|
|
|
if(hop <= 1 || (q = transbackward(tcp, iph)) == nil)
|
|
goto reset;
|
|
hnputs_csum(h4->tcpdst+0, nhgets(q->forward.raddr+IPv4off+0), h4->tcpcksum);
|
|
hnputs_csum(h4->tcpdst+2, nhgets(q->forward.raddr+IPv4off+2), h4->tcpcksum);
|
|
hnputs_csum(h4->tcpdport, q->forward.rport, h4->tcpcksum);
|
|
qunlock(tcp);
|
|
ipoput4(f, bp, 1, hop - 1, h4->tos, q);
|
|
return;
|
|
}
|
|
s = iphconv(iph);
|
|
|
|
/* trim off ip and tcp headers */
|
|
bp = trimblock(bp, hdrlen, length);
|
|
if(bp == nil){
|
|
tpriv->stats[LenErrs]++;
|
|
tpriv->stats[InErrs]++;
|
|
netlog(f, Logtcp, "tcp bad length after header trim off\n");
|
|
qunlock(tcp);
|
|
return;
|
|
}
|
|
|
|
/* if it's a listener, look for the right flags and get a new conv */
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
if(tcb->state == Listen){
|
|
if(seg.flags & RST){
|
|
limborst(s, &seg, source, dest, version);
|
|
qunlock(tcp);
|
|
freeblist(bp);
|
|
return;
|
|
}
|
|
|
|
/* if this is a new SYN, put the call into limbo */
|
|
if((seg.flags & SYN) && (seg.flags & ACK) == 0){
|
|
freeblist(bp);
|
|
limbo(s, source, dest, &seg, version);
|
|
qunlock(tcp);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* if there's a matching call in limbo, tcpincoming will
|
|
* return it in state Syn_received
|
|
*/
|
|
s = tcpincoming(s, &seg, source, dest, version);
|
|
if(s == nil)
|
|
goto reset;
|
|
}
|
|
|
|
/* The rest of the input state machine is run with the control block
|
|
* locked and implements the state machine directly out of the RFC.
|
|
* Out-of-band data is ignored - it was always a bad idea.
|
|
*/
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
if(waserror()){
|
|
qunlock(s);
|
|
nexterror();
|
|
}
|
|
qlock(s);
|
|
qunlock(tcp);
|
|
|
|
/* fix up window */
|
|
seg.wnd <<= tcb->rcv.scale;
|
|
|
|
/* every input packet in puts off the keep alive time out */
|
|
tcpsetkacounter(tcb);
|
|
|
|
switch(tcb->state) {
|
|
case Closed:
|
|
closed:
|
|
reason = "sending to Closed";
|
|
reset2:
|
|
freeblist(bp);
|
|
bp = nil;
|
|
sndrst(tcp, source, dest, length, &seg, version, reason, s);
|
|
goto raise;
|
|
case Syn_sent:
|
|
if(seg.flags & ACK) {
|
|
if(!seq_within(seg.ack, tcb->iss+1, tcb->snd.nxt)) {
|
|
reason = "bad seq in Syn_sent";
|
|
goto reset2;
|
|
}
|
|
}
|
|
if(seg.flags & RST) {
|
|
if(seg.flags & ACK)
|
|
localclose(s, Econrefused);
|
|
goto raise;
|
|
}
|
|
|
|
if(seg.flags & SYN) {
|
|
procsyn(s, &seg);
|
|
if(seg.flags & ACK){
|
|
update(s, &seg);
|
|
tcpsynackrtt(s);
|
|
tcpsetstate(s, Established);
|
|
tcpsetscale(s, tcb, seg.ws, tcb->scale);
|
|
}
|
|
else {
|
|
tcb->time = NOW;
|
|
tcpsetstate(s, Syn_received); /* DLP - shouldn't this be a reset? */
|
|
}
|
|
|
|
if(length != 0 || (seg.flags & FIN))
|
|
break;
|
|
freeblist(bp);
|
|
goto output;
|
|
}
|
|
qunlock(s);
|
|
poperror();
|
|
freeblist(bp);
|
|
return;
|
|
case Syn_received:
|
|
/* doesn't matter if it's the correct ack, we're just trying to set timing */
|
|
if(seg.flags & ACK)
|
|
tcpsynackrtt(s);
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* One DOS attack is to open connections to us and then forget about them,
|
|
* thereby tying up a conv at no long term cost to the attacker.
|
|
* This is an attempt to defeat these stateless DOS attacks. See
|
|
* corresponding code in tcpsendka().
|
|
*/
|
|
if(tcb->state != Syn_received && (seg.flags & RST) == 0){
|
|
if(tcpporthogdefense
|
|
&& seq_within(seg.ack, tcb->snd.una-(1<<31), tcb->snd.una-(1<<29))){
|
|
print("stateless hog %I.%d->%I.%d f %ux %lux - %lux - %lux\n",
|
|
source, seg.source, dest, seg.dest, seg.flags,
|
|
tcb->snd.una-(1<<31), seg.ack, tcb->snd.una-(1<<29));
|
|
localclose(s, "stateless hog");
|
|
}
|
|
}
|
|
|
|
/* Cut the data to fit the receive window */
|
|
tcprcvwin(s);
|
|
if(tcptrim(tcb, &seg, &bp, &length) == -1) {
|
|
if(seg.seq+1 != tcb->rcv.nxt || length != 1)
|
|
netlog(f, Logtcp, "tcp: trim: !inwind: seq %lud-%lud win %lud-%lud l %d from %I\n",
|
|
seg.seq, seg.seq + length - 1,
|
|
tcb->rcv.nxt, tcb->rcv.nxt + tcb->rcv.wnd-1, length, s->raddr);
|
|
update(s, &seg);
|
|
if(qlen(s->wq)+tcb->flgcnt == 0 && tcb->state == Closing) {
|
|
tcphalt(tpriv, &tcb->rtt_timer);
|
|
tcphalt(tpriv, &tcb->acktimer);
|
|
tcphalt(tpriv, &tcb->katimer);
|
|
tcpsetstate(s, Time_wait);
|
|
tcb->timer.start = MSL2*(1000 / MSPTICK);
|
|
tcpgo(tpriv, &tcb->timer);
|
|
}
|
|
if(!(seg.flags & RST)) {
|
|
tcb->flags |= FORCE;
|
|
goto output;
|
|
}
|
|
qunlock(s);
|
|
poperror();
|
|
return;
|
|
}
|
|
|
|
/* Cannot accept so answer with a rst */
|
|
if(length && tcb->state == Closed)
|
|
goto closed;
|
|
|
|
/* The segment is beyond the current receive pointer so
|
|
* queue the data in the resequence queue
|
|
*/
|
|
if(seg.seq != tcb->rcv.nxt)
|
|
if(length != 0 || (seg.flags & (SYN|FIN))) {
|
|
update(s, &seg);
|
|
if(addreseq(f, tcb, tpriv, &seg, &bp, length) < 0)
|
|
print("reseq %I.%d -> %I.%d\n", s->raddr, s->rport, s->laddr, s->lport);
|
|
tcb->flags |= FORCE; /* force duplicate ack; RFC 5681 §3.2 */
|
|
goto output;
|
|
}
|
|
|
|
if(tcb->nreseq > 0)
|
|
tcb->flags |= FORCE; /* filled hole in sequence space; RFC 5681 §3.2 */
|
|
|
|
/*
|
|
* keep looping till we've processed this packet plus any
|
|
* adjacent packets in the resequence queue
|
|
*/
|
|
for(;;) {
|
|
if(seg.flags & RST) {
|
|
if(tcb->state == Established) {
|
|
tpriv->stats[EstabResets]++;
|
|
if(tcb->rcv.nxt != seg.seq)
|
|
print("out of order RST rcvd: %I.%d -> %I.%d, rcv.nxt %lux seq %lux\n",
|
|
s->raddr, s->rport, s->laddr, s->lport, tcb->rcv.nxt, seg.seq);
|
|
}
|
|
localclose(s, Econrefused);
|
|
goto raise;
|
|
}
|
|
|
|
if((seg.flags&ACK) == 0)
|
|
goto raise;
|
|
|
|
switch(tcb->state) {
|
|
case Syn_received:
|
|
if(!seq_within(seg.ack, tcb->snd.una+1, tcb->snd.nxt)){
|
|
reason = "bad seq in Syn_received";
|
|
goto reset2;
|
|
}
|
|
update(s, &seg);
|
|
tcpsetstate(s, Established);
|
|
case Established:
|
|
case Close_wait:
|
|
update(s, &seg);
|
|
break;
|
|
case Finwait1:
|
|
update(s, &seg);
|
|
if(qlen(s->wq)+tcb->flgcnt == 0){
|
|
tcphalt(tpriv, &tcb->rtt_timer);
|
|
tcphalt(tpriv, &tcb->acktimer);
|
|
tcpsetkacounter(tcb);
|
|
tcb->time = NOW;
|
|
tcpsetstate(s, Finwait2);
|
|
tcb->katimer.start = MSL2 * (1000 / MSPTICK);
|
|
tcpgo(tpriv, &tcb->katimer);
|
|
}
|
|
break;
|
|
case Finwait2:
|
|
update(s, &seg);
|
|
break;
|
|
case Closing:
|
|
update(s, &seg);
|
|
if(qlen(s->wq)+tcb->flgcnt == 0) {
|
|
tcphalt(tpriv, &tcb->rtt_timer);
|
|
tcphalt(tpriv, &tcb->acktimer);
|
|
tcphalt(tpriv, &tcb->katimer);
|
|
tcpsetstate(s, Time_wait);
|
|
tcb->timer.start = MSL2*(1000 / MSPTICK);
|
|
tcpgo(tpriv, &tcb->timer);
|
|
}
|
|
break;
|
|
case Last_ack:
|
|
update(s, &seg);
|
|
if(qlen(s->wq)+tcb->flgcnt == 0) {
|
|
localclose(s, nil);
|
|
goto raise;
|
|
}
|
|
case Time_wait:
|
|
if(seg.flags & FIN)
|
|
tcb->flags |= FORCE;
|
|
if(tcb->timer.state != TcptimerON)
|
|
tcpgo(tpriv, &tcb->timer);
|
|
}
|
|
|
|
if((seg.flags&URG) && seg.urg) {
|
|
if(seq_gt(seg.urg + seg.seq, tcb->rcv.urg)) {
|
|
tcb->rcv.urg = seg.urg + seg.seq;
|
|
pullblock(&bp, seg.urg);
|
|
}
|
|
}
|
|
else
|
|
if(seq_gt(tcb->rcv.nxt, tcb->rcv.urg))
|
|
tcb->rcv.urg = tcb->rcv.nxt;
|
|
|
|
if(length == 0) {
|
|
freeblist(bp);
|
|
bp = nil;
|
|
}
|
|
else {
|
|
switch(tcb->state){
|
|
default:
|
|
/* Ignore segment text */
|
|
freeblist(bp);
|
|
bp = nil;
|
|
break;
|
|
|
|
case Syn_received:
|
|
case Established:
|
|
case Finwait1:
|
|
/* If we still have some data place on
|
|
* receive queue
|
|
*/
|
|
if(bp != nil) {
|
|
qpassnolim(s->rq, packblock(bp));
|
|
bp = nil;
|
|
}
|
|
tcb->rcv.nxt += length;
|
|
|
|
/*
|
|
* turn on the acktimer if there's something
|
|
* to ack
|
|
*/
|
|
if(tcb->acktimer.state != TcptimerON)
|
|
tcpgo(tpriv, &tcb->acktimer);
|
|
|
|
break;
|
|
case Finwait2:
|
|
reason = "send to Finwait2";
|
|
goto reset2;
|
|
}
|
|
}
|
|
|
|
if(seg.flags & FIN) {
|
|
tcb->flags |= FORCE;
|
|
|
|
switch(tcb->state) {
|
|
case Syn_received:
|
|
case Established:
|
|
tcb->rcv.nxt++;
|
|
tcpsetstate(s, Close_wait);
|
|
break;
|
|
case Finwait1:
|
|
tcb->rcv.nxt++;
|
|
if(qlen(s->wq)+tcb->flgcnt == 0) {
|
|
tcphalt(tpriv, &tcb->rtt_timer);
|
|
tcphalt(tpriv, &tcb->acktimer);
|
|
tcphalt(tpriv, &tcb->katimer);
|
|
tcpsetstate(s, Time_wait);
|
|
tcb->timer.start = MSL2*(1000/MSPTICK);
|
|
tcpgo(tpriv, &tcb->timer);
|
|
}
|
|
else
|
|
tcpsetstate(s, Closing);
|
|
break;
|
|
case Finwait2:
|
|
tcb->rcv.nxt++;
|
|
tcphalt(tpriv, &tcb->rtt_timer);
|
|
tcphalt(tpriv, &tcb->acktimer);
|
|
tcphalt(tpriv, &tcb->katimer);
|
|
tcpsetstate(s, Time_wait);
|
|
tcb->timer.start = MSL2 * (1000/MSPTICK);
|
|
tcpgo(tpriv, &tcb->timer);
|
|
break;
|
|
case Close_wait:
|
|
case Closing:
|
|
case Last_ack:
|
|
break;
|
|
case Time_wait:
|
|
tcpgo(tpriv, &tcb->timer);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* get next adjacent segment from the resequence queue.
|
|
* dump/trim any overlapping segments
|
|
*/
|
|
for(;;) {
|
|
if(tcb->reseq == nil)
|
|
goto output;
|
|
|
|
if(seq_ge(tcb->rcv.nxt, tcb->reseq->seg.seq) == 0)
|
|
goto output;
|
|
|
|
getreseq(tcb, &seg, &bp, &length);
|
|
|
|
tcprcvwin(s);
|
|
if(tcptrim(tcb, &seg, &bp, &length) == 0){
|
|
tcb->flags |= FORCE;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
output:
|
|
tcpoutput(s);
|
|
qunlock(s);
|
|
poperror();
|
|
return;
|
|
raise:
|
|
qunlock(s);
|
|
poperror();
|
|
freeblist(bp);
|
|
tcpkick(s);
|
|
}
|
|
|
|
/*
|
|
* always enters and exits with the s locked. We drop
|
|
* the lock to ipoput the packet so some care has to be
|
|
* taken by callers.
|
|
*/
|
|
static void
|
|
tcpoutput(Conv *s)
|
|
{
|
|
Tcp seg;
|
|
uint msgs;
|
|
Tcpctl *tcb;
|
|
Block *hbp, *bp;
|
|
int sndcnt;
|
|
ulong ssize, dsize, sent;
|
|
Fs *f;
|
|
Tcppriv *tpriv;
|
|
uchar version;
|
|
|
|
f = s->p->f;
|
|
tpriv = s->p->priv;
|
|
version = s->ipversion;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
|
|
/* force ack every 2*mss */
|
|
if((tcb->flags & FORCE) == 0)
|
|
if(tcb->rcv.nxt - tcb->rcv.ackptr >= 2*tcb->mss){
|
|
tpriv->stats[Delayack]++;
|
|
tcb->flags |= FORCE;
|
|
}
|
|
|
|
/* force ack if window opening */
|
|
if(0)
|
|
if((tcb->flags & FORCE) == 0){
|
|
tcprcvwin(s);
|
|
if((int)(tcb->rcv.wptr - tcb->rcv.wsnt) >= 2*tcb->mss){
|
|
tpriv->stats[Wopenack]++;
|
|
tcb->flags |= FORCE;
|
|
}
|
|
}
|
|
|
|
for(msgs = 0; msgs < 100; msgs++) {
|
|
switch(tcb->state) {
|
|
case Listen:
|
|
case Closed:
|
|
case Finwait2:
|
|
return;
|
|
}
|
|
|
|
/* Don't send anything else until our SYN has been acked */
|
|
if(tcb->snd.ptr != tcb->iss && (tcb->flags & SYNACK) == 0)
|
|
break;
|
|
|
|
/* force an ack when a window has opened up */
|
|
tcprcvwin(s);
|
|
if(tcb->rcv.blocked && tcb->rcv.wnd > 0){
|
|
tcb->rcv.blocked = 0;
|
|
tcb->flags |= FORCE;
|
|
}
|
|
|
|
sndcnt = qlen(s->wq)+tcb->flgcnt;
|
|
sent = tcb->snd.ptr - tcb->snd.una;
|
|
ssize = sndcnt;
|
|
if(tcb->snd.wnd == 0){
|
|
/* zero window probe */
|
|
if(sent > 0)
|
|
if(!(tcb->flags & FORCE))
|
|
break; /* already probing, rto re-probes */
|
|
if(ssize < sent)
|
|
ssize = 0;
|
|
else{
|
|
ssize -= sent;
|
|
if(ssize > 0)
|
|
ssize = 1;
|
|
}
|
|
} else {
|
|
/* calculate usable segment size */
|
|
if(ssize > tcb->cwind)
|
|
ssize = tcb->cwind;
|
|
if(ssize > tcb->snd.wnd)
|
|
ssize = tcb->snd.wnd;
|
|
|
|
if(ssize < sent)
|
|
ssize = 0;
|
|
else {
|
|
ssize -= sent;
|
|
if(ssize > tcb->mss)
|
|
ssize = tcb->mss;
|
|
}
|
|
}
|
|
|
|
dsize = ssize;
|
|
seg.urg = 0;
|
|
|
|
if(!(tcb->flags & FORCE)){
|
|
if(ssize == 0)
|
|
break;
|
|
if(ssize < tcb->mss)
|
|
if(tcb->snd.nxt == tcb->snd.ptr)
|
|
if(sent > TCPREXMTTHRESH*tcb->mss)
|
|
break;
|
|
}
|
|
|
|
tcb->flags &= ~FORCE;
|
|
|
|
/* By default we will generate an ack */
|
|
tcphalt(tpriv, &tcb->acktimer);
|
|
seg.source = s->lport;
|
|
seg.dest = s->rport;
|
|
seg.flags = ACK;
|
|
seg.mss = 0;
|
|
seg.ws = 0;
|
|
seg.update = 0;
|
|
switch(tcb->state){
|
|
case Syn_sent:
|
|
seg.flags = 0;
|
|
if(tcb->snd.ptr == tcb->iss){
|
|
seg.flags |= SYN;
|
|
dsize--;
|
|
seg.mss = tcb->mss;
|
|
seg.ws = tcb->scale;
|
|
}
|
|
break;
|
|
case Syn_received:
|
|
/*
|
|
* don't send any data with a SYN/ACK packet
|
|
* because Linux rejects the packet in its
|
|
* attempt to solve the SYN attack problem
|
|
*/
|
|
if(tcb->snd.ptr == tcb->iss){
|
|
seg.flags |= SYN;
|
|
dsize = 0;
|
|
ssize = 1;
|
|
seg.mss = tcb->mss;
|
|
seg.ws = tcb->scale;
|
|
}
|
|
break;
|
|
}
|
|
seg.seq = tcb->snd.ptr;
|
|
seg.ack = tcb->rcv.nxt;
|
|
seg.wnd = tcb->rcv.wnd;
|
|
|
|
/* Pull out data to send */
|
|
bp = nil;
|
|
if(dsize != 0) {
|
|
bp = qcopy(s->wq, dsize, sent);
|
|
if(BLEN(bp) != dsize) {
|
|
seg.flags |= FIN;
|
|
dsize--;
|
|
}
|
|
}
|
|
|
|
if(sent+dsize == sndcnt && dsize)
|
|
seg.flags |= PSH;
|
|
|
|
tcb->snd.ptr += ssize;
|
|
|
|
/* Pull up the send pointer so we can accept acks
|
|
* for this window
|
|
*/
|
|
if(seq_gt(tcb->snd.ptr,tcb->snd.nxt))
|
|
tcb->snd.nxt = tcb->snd.ptr;
|
|
|
|
/* Build header, link data and compute cksum */
|
|
switch(version){
|
|
case V4:
|
|
tcb->protohdr.tcp4hdr.vihl = IP_VER4;
|
|
hbp = htontcp4(&seg, bp, &tcb->protohdr.tcp4hdr, tcb);
|
|
break;
|
|
case V6:
|
|
tcb->protohdr.tcp6hdr.vcf[0] = IP_VER6;
|
|
hbp = htontcp6(&seg, bp, &tcb->protohdr.tcp6hdr, tcb);
|
|
break;
|
|
default:
|
|
hbp = nil; /* to suppress a warning */
|
|
panic("tcpoutput: version %d", version);
|
|
}
|
|
|
|
/* Start the transmission timers if there is new data and we
|
|
* expect acknowledges
|
|
*/
|
|
if(ssize != 0){
|
|
if(tcb->timer.state != TcptimerON){
|
|
tcb->time = NOW;
|
|
tcb->timeuna = tcb->snd.una;
|
|
tcpgo(tpriv, &tcb->timer);
|
|
}
|
|
|
|
/* If round trip timer isn't running, start it.
|
|
* measure the longest packet only in case the
|
|
* transmission time dominates RTT
|
|
*/
|
|
if(tcb->snd.retransmit == 0)
|
|
if(tcb->rtt_timer.state != TcptimerON)
|
|
if(ssize == tcb->mss) {
|
|
tcpgo(tpriv, &tcb->rtt_timer);
|
|
tcb->rttseq = tcb->snd.ptr;
|
|
}
|
|
}
|
|
|
|
tpriv->stats[OutSegs]++;
|
|
if(tcb->snd.retransmit)
|
|
tpriv->stats[RetransSegsSent]++;
|
|
tcb->rcv.ackptr = seg.ack;
|
|
tcb->rcv.wsnt = tcb->rcv.wptr;
|
|
|
|
/* put off the next keep alive */
|
|
tcpgo(tpriv, &tcb->katimer);
|
|
|
|
switch(version){
|
|
case V4:
|
|
if(ipoput4(f, hbp, 0, s->ttl, s->tos, s) < 0)
|
|
localclose(s, Enoroute);
|
|
break;
|
|
case V6:
|
|
if(ipoput6(f, hbp, 0, s->ttl, s->tos, s) < 0)
|
|
localclose(s, Enoroute);
|
|
break;
|
|
}
|
|
if((msgs%4) == 3){
|
|
qunlock(s);
|
|
qlock(s);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* the BSD convention (hack?) for keep alives. resend last uchar acked.
|
|
*/
|
|
static int
|
|
tcpsendka(Conv *s)
|
|
{
|
|
Tcp seg;
|
|
Tcpctl *tcb;
|
|
Block *hbp,*dbp;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
|
|
dbp = nil;
|
|
memset(&seg, 0, sizeof seg);
|
|
seg.urg = 0;
|
|
seg.source = s->lport;
|
|
seg.dest = s->rport;
|
|
seg.flags = ACK|PSH;
|
|
seg.mss = 0;
|
|
seg.ws = 0;
|
|
if(tcpporthogdefense)
|
|
seg.seq = tcb->snd.una-(1<<30)-nrand(1<<20);
|
|
else
|
|
seg.seq = tcb->snd.una-1;
|
|
seg.ack = tcb->rcv.nxt;
|
|
tcb->rcv.ackptr = seg.ack;
|
|
tcprcvwin(s);
|
|
seg.wnd = tcb->rcv.wnd;
|
|
if(tcb->state == Finwait2){
|
|
seg.flags |= FIN;
|
|
} else {
|
|
dbp = allocb(1);
|
|
dbp->wp++;
|
|
}
|
|
|
|
if(isv4(s->raddr)) {
|
|
/* Build header, link data and compute cksum */
|
|
tcb->protohdr.tcp4hdr.vihl = IP_VER4;
|
|
hbp = htontcp4(&seg, dbp, &tcb->protohdr.tcp4hdr, tcb);
|
|
return ipoput4(s->p->f, hbp, 0, s->ttl, s->tos, s);
|
|
}
|
|
else {
|
|
/* Build header, link data and compute cksum */
|
|
tcb->protohdr.tcp6hdr.vcf[0] = IP_VER6;
|
|
hbp = htontcp6(&seg, dbp, &tcb->protohdr.tcp6hdr, tcb);
|
|
return ipoput6(s->p->f, hbp, 0, s->ttl, s->tos, s);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* set connection to time out after 12 minutes
|
|
*/
|
|
static void
|
|
tcpsetkacounter(Tcpctl *tcb)
|
|
{
|
|
tcb->kacounter = (12 * 60 * 1000) / (tcb->katimer.start*MSPTICK);
|
|
if(tcb->kacounter < 3)
|
|
tcb->kacounter = 3;
|
|
}
|
|
|
|
/*
|
|
* if we've timed out, close the connection
|
|
* otherwise, send a keepalive and restart the timer
|
|
*/
|
|
static void
|
|
tcpkeepalive(void *v)
|
|
{
|
|
Tcpctl *tcb;
|
|
Conv *s;
|
|
|
|
s = v;
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
if(waserror()){
|
|
qunlock(s);
|
|
nexterror();
|
|
}
|
|
qlock(s);
|
|
if(tcb->state != Closed){
|
|
if(--(tcb->kacounter) <= 0) {
|
|
localclose(s, Etimedout);
|
|
} else if(tcpsendka(s) < 0) {
|
|
localclose(s, Enoroute);
|
|
} else {
|
|
tcpgo(s->p->priv, &tcb->katimer);
|
|
}
|
|
}
|
|
qunlock(s);
|
|
poperror();
|
|
}
|
|
|
|
/*
|
|
* start keepalive timer
|
|
*/
|
|
static char*
|
|
tcpstartka(Conv *s, char **f, int n)
|
|
{
|
|
Tcpctl *tcb;
|
|
int x;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
if(tcb->state != Established)
|
|
return "connection must be in Establised state";
|
|
if(n > 1){
|
|
x = atoi(f[1]);
|
|
if(x >= MSPTICK)
|
|
tcb->katimer.start = x/MSPTICK;
|
|
}
|
|
tcpsetkacounter(tcb);
|
|
tcpgo(s->p->priv, &tcb->katimer);
|
|
|
|
return nil;
|
|
}
|
|
|
|
/*
|
|
* turn checksums on/off
|
|
*/
|
|
static char*
|
|
tcpsetchecksum(Conv *s, char **f, int)
|
|
{
|
|
Tcpctl *tcb;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
tcb->nochecksum = !atoi(f[1]);
|
|
|
|
return nil;
|
|
}
|
|
|
|
/*
|
|
* retransmit (at most) one segment at snd.una.
|
|
* preserve cwind & snd.ptr
|
|
*/
|
|
static void
|
|
tcprxmit(Conv *s)
|
|
{
|
|
Tcpctl *tcb;
|
|
Tcppriv *tpriv;
|
|
ulong tcwind, tptr;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
tcb->flags |= RETRAN|FORCE;
|
|
|
|
tptr = tcb->snd.ptr;
|
|
tcwind = tcb->cwind;
|
|
tcb->snd.ptr = tcb->snd.una;
|
|
tcb->cwind = tcb->mss;
|
|
tcb->snd.retransmit = 1;
|
|
tcpoutput(s);
|
|
tcb->snd.retransmit = 0;
|
|
tcb->cwind = tcwind;
|
|
tcb->snd.ptr = tptr;
|
|
|
|
tpriv = s->p->priv;
|
|
tpriv->stats[RetransSegs]++;
|
|
}
|
|
|
|
/*
|
|
* todo: RFC 4138 F-RTO
|
|
*/
|
|
static void
|
|
tcptimeout(void *arg)
|
|
{
|
|
Conv *s;
|
|
Tcpctl *tcb;
|
|
int maxback;
|
|
Tcppriv *tpriv;
|
|
|
|
s = (Conv*)arg;
|
|
tpriv = s->p->priv;
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
|
|
if(waserror()){
|
|
qunlock(s);
|
|
nexterror();
|
|
}
|
|
qlock(s);
|
|
switch(tcb->state){
|
|
default:
|
|
tcb->backoff++;
|
|
if(tcb->state == Syn_sent)
|
|
maxback = MAXBACKMS/2;
|
|
else
|
|
maxback = MAXBACKMS;
|
|
tcb->backedoff += tcb->timer.start * MSPTICK;
|
|
if(tcb->backedoff >= maxback) {
|
|
localclose(s, Etimedout);
|
|
break;
|
|
}
|
|
netlog(s->p->f, Logtcprxmt, "rxm %d/%d %ldms %lud rto %d %lud %s\n",
|
|
tcb->srtt, tcb->mdev, NOW-tcb->time,
|
|
tcb->snd.una-tcb->timeuna, tcb->snd.rto, tcb->snd.ptr,
|
|
tcpstates[s->state]);
|
|
tcpsettimer(tcb);
|
|
if(tcb->snd.rto == 0)
|
|
tcpcongestion(tcb);
|
|
tcprxmit(s);
|
|
tcb->snd.ptr = tcb->snd.una;
|
|
tcb->cwind = tcb->mss;
|
|
tcb->snd.rto = 1;
|
|
tpriv->stats[RetransTimeouts]++;
|
|
|
|
if(tcb->snd.recovery){
|
|
tcb->snd.dupacks = 0; /* reno rto */
|
|
tcb->snd.recovery = 0;
|
|
tpriv->stats[RecoveryRTO]++;
|
|
tcb->snd.rxt = tcb->snd.nxt;
|
|
netlog(s->p->f, Logtcpwin,
|
|
"rto recovery rxt @%lud\n", tcb->snd.nxt);
|
|
}
|
|
|
|
tcb->abcbytes = 0;
|
|
break;
|
|
case Time_wait:
|
|
localclose(s, nil);
|
|
break;
|
|
case Closed:
|
|
break;
|
|
}
|
|
qunlock(s);
|
|
poperror();
|
|
}
|
|
|
|
static int
|
|
inwindow(Tcpctl *tcb, int seq)
|
|
{
|
|
return seq_within(seq, tcb->rcv.nxt, tcb->rcv.nxt+tcb->rcv.wnd-1);
|
|
}
|
|
|
|
/*
|
|
* set up state for a received SYN (or SYN ACK) packet
|
|
*/
|
|
static void
|
|
procsyn(Conv *s, Tcp *seg)
|
|
{
|
|
Tcpctl *tcb;
|
|
Tcppriv *tpriv;
|
|
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
tcb->flags |= FORCE;
|
|
|
|
tcb->rcv.nxt = seg->seq + 1;
|
|
tcb->rcv.wptr = tcb->rcv.nxt;
|
|
tcb->rcv.wsnt = 0;
|
|
tcb->rcv.urg = tcb->rcv.nxt;
|
|
tcb->irs = seg->seq;
|
|
|
|
/* our sending max segment size cannot be bigger than what he asked for */
|
|
if(seg->mss != 0 && seg->mss < tcb->mss) {
|
|
tcb->mss = seg->mss;
|
|
tpriv = s->p->priv;
|
|
tpriv->stats[Mss] = tcb->mss;
|
|
}
|
|
|
|
/* if the server does not support ws option, disable window scaling */
|
|
if(seg->ws == 0){
|
|
tcb->scale = 0;
|
|
tcb->snd.scale = 0;
|
|
}
|
|
|
|
tcb->snd.wnd = seg->wnd;
|
|
initialwindow(tcb);
|
|
}
|
|
|
|
static int
|
|
dumpreseq(Tcpctl *tcb)
|
|
{
|
|
Reseq *r, *next;
|
|
|
|
for(r = tcb->reseq; r != nil; r = next){
|
|
next = r->next;
|
|
freeblist(r->bp);
|
|
free(r);
|
|
}
|
|
tcb->reseq = nil;
|
|
tcb->nreseq = 0;
|
|
tcb->reseqlen = 0;
|
|
return -1;
|
|
}
|
|
|
|
static void
|
|
logreseq(Fs *f, Reseq *r, ulong n)
|
|
{
|
|
char *s;
|
|
|
|
for(; r != nil; r = r->next){
|
|
s = nil;
|
|
if(r->next == nil && r->seg.seq != n)
|
|
s = "hole/end";
|
|
else if(r->next == nil)
|
|
s = "end";
|
|
else if(r->seg.seq != n)
|
|
s = "hole";
|
|
if(s != nil)
|
|
netlog(f, Logtcp, "%s %lud-%lud (%ld) %#ux\n", s,
|
|
n, r->seg.seq, r->seg.seq-n, r->seg.flags);
|
|
n = r->seg.seq + r->seg.len;
|
|
}
|
|
}
|
|
|
|
static int
|
|
addreseq(Fs *f, Tcpctl *tcb, Tcppriv *tpriv, Tcp *seg, Block **bpp, ushort length)
|
|
{
|
|
Reseq *rp, **rr;
|
|
int qmax;
|
|
|
|
rp = malloc(sizeof(Reseq));
|
|
if(rp == nil){
|
|
freeblist(*bpp); /* *bpp always consumed by addreseq */
|
|
*bpp = nil;
|
|
return 0;
|
|
}
|
|
|
|
rp->seg = *seg;
|
|
rp->bp = *bpp;
|
|
rp->length = length;
|
|
*bpp = nil;
|
|
|
|
tcb->reseqlen += length;
|
|
tcb->nreseq++;
|
|
|
|
/* Place on reassembly list sorting by starting seq number */
|
|
for(rr = &tcb->reseq;; rr = &(*rr)->next)
|
|
if(*rr == nil || seq_lt(seg->seq, (*rr)->seg.seq)){
|
|
rp->next = *rr;
|
|
*rr = rp;
|
|
tpriv->stats[Resequenced]++;
|
|
if(rp->next != nil)
|
|
tpriv->stats[OutOfOrder]++;
|
|
break;
|
|
}
|
|
|
|
qmax = tcb->window;
|
|
if(tcb->reseqlen > qmax){
|
|
netlog(f, Logtcp, "tcp: reseq: queue > window: %d > %d; %d packets\n", tcb->reseqlen, qmax, tcb->nreseq);
|
|
logreseq(f, tcb->reseq, tcb->rcv.nxt);
|
|
tpriv->stats[ReseqBytelim]++;
|
|
return dumpreseq(tcb);
|
|
}
|
|
qmax = tcb->window / tcb->mss; /* ~190 for qscale==2, 390 for qscale=3 */
|
|
if(tcb->nreseq > qmax){
|
|
netlog(f, Logtcp, "resequence queue > packets: %d %d; %d bytes\n", tcb->nreseq, qmax, tcb->reseqlen);
|
|
logreseq(f, tcb->reseq, tcb->rcv.nxt);
|
|
tpriv->stats[ReseqPktlim]++;
|
|
return dumpreseq(tcb);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
getreseq(Tcpctl *tcb, Tcp *seg, Block **bp, ushort *length)
|
|
{
|
|
Reseq *rp;
|
|
|
|
rp = tcb->reseq;
|
|
if(rp == nil)
|
|
return;
|
|
|
|
tcb->reseq = rp->next;
|
|
|
|
*seg = rp->seg;
|
|
*bp = rp->bp;
|
|
*length = rp->length;
|
|
|
|
tcb->nreseq--;
|
|
tcb->reseqlen -= rp->length;
|
|
|
|
free(rp);
|
|
}
|
|
|
|
static int
|
|
tcptrim(Tcpctl *tcb, Tcp *seg, Block **bp, ushort *length)
|
|
{
|
|
ushort len;
|
|
uchar accept;
|
|
int dupcnt, excess;
|
|
|
|
accept = 0;
|
|
len = *length;
|
|
if(seg->flags & SYN)
|
|
len++;
|
|
if(seg->flags & FIN)
|
|
len++;
|
|
|
|
if(tcb->rcv.wnd == 0) {
|
|
if(len == 0 && seg->seq == tcb->rcv.nxt)
|
|
return 0;
|
|
}
|
|
else {
|
|
/* Some part of the segment should be in the window */
|
|
if(inwindow(tcb,seg->seq))
|
|
accept++;
|
|
else
|
|
if(len != 0) {
|
|
if(inwindow(tcb, seg->seq+len-1) ||
|
|
seq_within(tcb->rcv.nxt, seg->seq,seg->seq+len-1))
|
|
accept++;
|
|
}
|
|
}
|
|
if(!accept) {
|
|
freeblist(*bp);
|
|
*bp = nil;
|
|
return -1;
|
|
}
|
|
dupcnt = tcb->rcv.nxt - seg->seq;
|
|
if(dupcnt > 0){
|
|
tcb->rerecv += dupcnt;
|
|
if(seg->flags & SYN){
|
|
seg->flags &= ~SYN;
|
|
seg->seq++;
|
|
|
|
if(seg->urg > 1)
|
|
seg->urg--;
|
|
else
|
|
seg->flags &= ~URG;
|
|
dupcnt--;
|
|
}
|
|
if(dupcnt > 0){
|
|
pullblock(bp, (ushort)dupcnt);
|
|
seg->seq += dupcnt;
|
|
*length -= dupcnt;
|
|
|
|
if(seg->urg > dupcnt)
|
|
seg->urg -= dupcnt;
|
|
else {
|
|
seg->flags &= ~URG;
|
|
seg->urg = 0;
|
|
}
|
|
}
|
|
}
|
|
excess = seg->seq + *length - (tcb->rcv.nxt + tcb->rcv.wnd);
|
|
if(excess > 0) {
|
|
tcb->rerecv += excess;
|
|
*length -= excess;
|
|
*bp = trimblock(*bp, 0, *length);
|
|
if(*bp == nil)
|
|
panic("presotto is a boofhead");
|
|
seg->flags &= ~FIN;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
tcpadvise(Proto *tcp, Block *bp, char *msg)
|
|
{
|
|
Tcp4hdr *h4;
|
|
Tcp6hdr *h6;
|
|
uchar source[IPaddrlen];
|
|
uchar dest[IPaddrlen];
|
|
ushort psource, pdest;
|
|
Iphash *iph;
|
|
Tcpctl *tcb;
|
|
Conv *s;
|
|
|
|
h4 = (Tcp4hdr*)(bp->rp);
|
|
h6 = (Tcp6hdr*)(bp->rp);
|
|
|
|
if((h4->vihl&0xF0)==IP_VER4) {
|
|
v4tov6(dest, h4->tcpdst);
|
|
v4tov6(source, h4->tcpsrc);
|
|
psource = nhgets(h4->tcpsport);
|
|
pdest = nhgets(h4->tcpdport);
|
|
} else {
|
|
ipmove(dest, h6->tcpdst);
|
|
ipmove(source, h6->tcpsrc);
|
|
psource = nhgets(h6->tcpsport);
|
|
pdest = nhgets(h6->tcpdport);
|
|
}
|
|
|
|
/* Look for a connection (source/dest reversed; this is the original packet we sent) */
|
|
qlock(tcp);
|
|
iph = iphtlook(&((Tcppriv*)tcp->priv)->ht, dest, pdest, source, psource);
|
|
if(iph == nil)
|
|
goto raise;
|
|
if(iph->trans){
|
|
Translation *q;
|
|
|
|
if((q = transbackward(tcp, iph)) == nil)
|
|
goto raise;
|
|
|
|
/* h4->tcplen is the ip header checksum */
|
|
hnputs_csum(h4->tcpsrc+0, nhgets(q->forward.raddr+IPv4off+0), h4->tcplen);
|
|
hnputs_csum(h4->tcpsrc+2, nhgets(q->forward.raddr+IPv4off+2), h4->tcplen);
|
|
|
|
/* dont bother fixing tcp checksum, packet is most likely truncated */
|
|
hnputs(h4->tcpsport, q->forward.rport);
|
|
qunlock(tcp);
|
|
|
|
icmpproxyadvice(tcp->f, bp, h4->tcpsrc);
|
|
return;
|
|
}
|
|
s = iphconv(iph);
|
|
if(s->ignoreadvice || s->state == Closed)
|
|
goto raise;
|
|
qlock(s);
|
|
qunlock(tcp);
|
|
tcb = (Tcpctl*)s->ptcl;
|
|
if(tcb->state == Syn_sent)
|
|
localclose(s, msg);
|
|
qunlock(s);
|
|
freeblist(bp);
|
|
return;
|
|
raise:
|
|
qunlock(tcp);
|
|
freeblist(bp);
|
|
}
|
|
|
|
static Block*
|
|
tcpforward(Proto *tcp, Block *bp, Route *r)
|
|
{
|
|
uchar da[IPaddrlen], sa[IPaddrlen];
|
|
ushort dp, sp;
|
|
Tcp4hdr *h4;
|
|
Translation *q;
|
|
|
|
h4 = (Tcp4hdr*)(bp->rp);
|
|
v4tov6(da, h4->tcpdst);
|
|
v4tov6(sa, h4->tcpsrc);
|
|
dp = nhgets(h4->tcpdport);
|
|
sp = nhgets(h4->tcpsport);
|
|
|
|
qlock(tcp);
|
|
q = transforward(tcp, &((Tcppriv*)tcp->priv)->ht, sa, sp, da, dp, r);
|
|
if(q == nil){
|
|
qunlock(tcp);
|
|
freeblist(bp);
|
|
return nil;
|
|
}
|
|
hnputs_csum(h4->tcpsrc+0, nhgets(q->backward.laddr+IPv4off+0), h4->tcpcksum);
|
|
hnputs_csum(h4->tcpsrc+2, nhgets(q->backward.laddr+IPv4off+2), h4->tcpcksum);
|
|
hnputs_csum(h4->tcpsport, q->backward.lport, h4->tcpcksum);
|
|
qunlock(tcp);
|
|
|
|
return bp;
|
|
}
|
|
|
|
static char*
|
|
tcpporthogdefensectl(char *val)
|
|
{
|
|
if(strcmp(val, "on") == 0)
|
|
tcpporthogdefense = 1;
|
|
else if(strcmp(val, "off") == 0)
|
|
tcpporthogdefense = 0;
|
|
else
|
|
return "unknown value for tcpporthogdefense";
|
|
return nil;
|
|
}
|
|
|
|
/* called with c qlocked */
|
|
static char*
|
|
tcpctl(Conv* c, char** f, int n)
|
|
{
|
|
if(n == 1 && strcmp(f[0], "close") == 0)
|
|
return tcpclose(c), nil;
|
|
if(n == 1 && strcmp(f[0], "hangup") == 0)
|
|
return tcphangup(c);
|
|
if(n >= 1 && strcmp(f[0], "keepalive") == 0)
|
|
return tcpstartka(c, f, n);
|
|
if(n >= 1 && strcmp(f[0], "checksum") == 0)
|
|
return tcpsetchecksum(c, f, n);
|
|
if(n >= 1 && strcmp(f[0], "tcpporthogdefense") == 0)
|
|
return tcpporthogdefensectl(f[1]);
|
|
return "unknown control request";
|
|
}
|
|
|
|
static int
|
|
tcpstats(Proto *tcp, char *buf, int len)
|
|
{
|
|
Tcppriv *priv;
|
|
char *p, *e;
|
|
int i;
|
|
|
|
priv = tcp->priv;
|
|
p = buf;
|
|
e = p+len;
|
|
for(i = 0; i < Nstats; i++)
|
|
p = seprint(p, e, "%s: %llud\n", statnames[i], priv->stats[i]);
|
|
return p - buf;
|
|
}
|
|
|
|
/*
|
|
* garbage collect any stale conversations:
|
|
* - SYN received but no SYN-ACK after 5 seconds (could be the SYN attack)
|
|
* - Finwait2 after 5 minutes
|
|
*
|
|
* this is called whenever we run out of channels. Both checks are
|
|
* of questionable validity so we try to use them only when we're
|
|
* up against the wall.
|
|
*/
|
|
static int
|
|
tcpgc(Proto *tcp)
|
|
{
|
|
Conv *c, **pp, **ep;
|
|
int n;
|
|
Tcpctl *tcb;
|
|
|
|
|
|
n = 0;
|
|
ep = &tcp->conv[tcp->nc];
|
|
for(pp = tcp->conv; pp < ep; pp++) {
|
|
c = *pp;
|
|
if(c == nil)
|
|
break;
|
|
if(!canqlock(c))
|
|
continue;
|
|
tcb = (Tcpctl*)c->ptcl;
|
|
switch(tcb->state){
|
|
case Syn_received:
|
|
if(NOW - tcb->time > 5000){
|
|
localclose(c, Etimedout);
|
|
n++;
|
|
}
|
|
break;
|
|
case Finwait2:
|
|
if(NOW - tcb->time > 5*60*1000){
|
|
localclose(c, Etimedout);
|
|
n++;
|
|
}
|
|
break;
|
|
}
|
|
qunlock(c);
|
|
}
|
|
return n;
|
|
}
|
|
|
|
static void
|
|
tcpsettimer(Tcpctl *tcb)
|
|
{
|
|
int x;
|
|
|
|
/* round trip dependency */
|
|
x = backoff(tcb->backoff) *
|
|
(tcb->mdev + (tcb->srtt>>LOGAGAIN) + MSPTICK) / MSPTICK;
|
|
|
|
/* bounded twixt 0.3 and 64 seconds */
|
|
if(x < 300/MSPTICK)
|
|
x = 300/MSPTICK;
|
|
else if(x > (64000/MSPTICK))
|
|
x = 64000/MSPTICK;
|
|
tcb->timer.start = x;
|
|
}
|
|
|
|
void
|
|
tcpinit(Fs *fs)
|
|
{
|
|
Proto *tcp;
|
|
Tcppriv *tpriv;
|
|
|
|
tcp = smalloc(sizeof(Proto));
|
|
tpriv = tcp->priv = smalloc(sizeof(Tcppriv));
|
|
tcp->name = "tcp";
|
|
tcp->connect = tcpconnect;
|
|
tcp->announce = tcpannounce;
|
|
tcp->ctl = tcpctl;
|
|
tcp->state = tcpstate;
|
|
tcp->create = tcpcreate;
|
|
tcp->close = tcpclose;
|
|
tcp->rcv = tcpiput;
|
|
tcp->advise = tcpadvise;
|
|
tcp->forward = tcpforward;
|
|
tcp->stats = tcpstats;
|
|
tcp->inuse = tcpinuse;
|
|
tcp->gc = tcpgc;
|
|
tcp->ipproto = IP_TCPPROTO;
|
|
tcp->nc = scalednconv();
|
|
tcp->ptclsize = sizeof(Tcpctl);
|
|
tpriv->stats[MaxConn] = tcp->nc;
|
|
|
|
Fsproto(fs, tcp);
|
|
}
|
|
|
|
static void
|
|
tcpsetscale(Conv *s, Tcpctl *tcb, ushort rcvscale, ushort sndscale)
|
|
{
|
|
/*
|
|
* guess at reasonable queue sizes. there's no current way
|
|
* to know how many nic receive buffers we can safely tie up in the
|
|
* tcp stack, and we don't adjust our queues to maximize throughput
|
|
* and minimize bufferbloat. n.b. the offer (rcvscale) needs to be
|
|
* respected, but we still control our own buffer commitment by
|
|
* keeping a seperate qscale.
|
|
*/
|
|
tcb->rcv.scale = rcvscale & 0xff;
|
|
tcb->snd.scale = sndscale & 0xff;
|
|
tcb->qscale = rcvscale & 0xff;
|
|
if(rcvscale > Maxqscale)
|
|
tcb->qscale = Maxqscale;
|
|
|
|
if(rcvscale != tcb->rcv.scale)
|
|
netlog(s->p->f, Logtcp, "tcpsetscale: window %lud qlen %d >> window %ud lport %d\n",
|
|
tcb->window, qlen(s->rq), QMAX<<tcb->qscale, s->lport);
|
|
tcb->window = QMAX<<tcb->qscale;
|
|
tcb->ssthresh = tcb->window;
|
|
|
|
/*
|
|
* it's important to set wq large enough to cover the full
|
|
* bandwidth-delay product. it's possible to be in loss
|
|
* recovery with a big window, and we need to keep sending
|
|
* into the inflated window. the difference can be huge
|
|
* for even modest (70ms) ping times.
|
|
*/
|
|
qsetlimit(s->rq, QMAX<<tcb->qscale);
|
|
qsetlimit(s->wq, QMAX<<tcb->qscale);
|
|
tcprcvwin(s);
|
|
}
|