d43d79bda4
The IPv4 ARP cache used to indefinitely buffer packets in the Arpent hold list. This is bad in case of a router, because it opens a 1 second (retransmit time) window to leak all the to be forwarded packets. This change makes the ipv4 arp code path similar to the IPv6 neighbour solicitation path, using the retransmit process to time out old entries (after 3 arp retransmits => 3 seconds). A new function arpcontinue() has been added that unifies the point when we schedule the (ipv6 sol retransmit) / (ipv4 arp timeout) and reduce the hold queue to the last packet and unlock the cache. As a bonus, we also now send a icmp host unreachable notification for the dropped packets.
187 lines
4.5 KiB
C
187 lines
4.5 KiB
C
/*
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* Internet Protocol Version 6
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*
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* rfc2460 defines the protocol, rfc2461 neighbour discovery, and
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* rfc2462 address autoconfiguration. rfc4443 defines ICMP; was rfc2463.
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* rfc4291 defines the address architecture (including prefices), was rfc3513.
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* rfc4007 defines the scoped address architecture.
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*
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* global unicast is anything but unspecified (::), loopback (::1),
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* multicast (ff00::/8), and link-local unicast (fe80::/10).
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*
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* site-local (fec0::/10) is now deprecated, originally by rfc3879.
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*
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* Unique Local IPv6 Unicast Addresses are defined by rfc4193.
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* prefix is fc00::/7, scope is global, routing is limited to roughly a site.
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*/
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#define isv6mcast(addr) ((addr)[0] == 0xff)
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#define islinklocal(addr) ((addr)[0] == 0xfe && ((addr)[1] & 0xc0) == 0x80)
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#define optexsts(np) (nhgets((np)->ploadlen) > 24)
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#define issmcast(addr) (memcmp((addr), v6solicitednode, 13) == 0)
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#ifndef MIN
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#define MIN(a, b) ((a) <= (b)? (a): (b))
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#endif
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enum { /* Header Types */
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HBH = 0, /* hop-by-hop multicast routing protocol */
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ICMP = 1,
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IGMP = 2,
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GGP = 3,
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IPINIP = 4,
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ST = 5,
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TCP = 6,
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UDP = 17,
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ISO_TP4 = 29,
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RH = 43,
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FH = 44,
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IDRP = 45,
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RSVP = 46,
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AH = 51,
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ESP = 52,
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ICMPv6 = 58,
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NNH = 59,
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DOH = 60,
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ISO_IP = 80,
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IGRP = 88,
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OSPF = 89,
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Maxhdrtype = 256,
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};
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enum {
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/* multicast flags and scopes */
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// Well_known_flg = 0,
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// Transient_flg = 1,
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// Interface_local_scop = 1,
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Link_local_scop = 2,
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// Site_local_scop = 5,
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// Org_local_scop = 8,
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Global_scop = 14,
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/* various prefix lengths */
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SOLN_PREF_LEN = 13,
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/* icmpv6 unreachability codes */
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Icmp6_no_route = 0,
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Icmp6_ad_prohib = 1,
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Icmp6_out_src_scope = 2,
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Icmp6_adr_unreach = 3,
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Icmp6_port_unreach = 4,
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Icmp6_gress_src_fail = 5,
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Icmp6_rej_route = 6,
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Icmp6_unknown = 7, /* our own invention for internal use */
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/* various flags & constants */
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v6MINTU = 1280,
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HOP_LIMIT = 255,
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IP6HDR = 40, /* sizeof(Ip6hdr) = 8 + 2*16 */
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IP6FHDR = 8, /* sizeof(Fraghdr6) */
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/* option types */
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/* neighbour discovery */
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SRC_LLADDR = 1,
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TARGET_LLADDR = 2,
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PREFIX_INFO = 3,
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REDIR_HEADER = 4,
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MTU_OPTION = 5,
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/* new since rfc2461; see iana.org/assignments/icmpv6-parameters */
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V6nd_home = 8,
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V6nd_srcaddrs = 9, /* rfc3122 */
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V6nd_ip = 17,
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/* /lib/rfc/drafts/draft-jeong-dnsop-ipv6-dns-discovery-12.txt */
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V6nd_rdns = 25,
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/* plan 9 extensions */
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V6nd_9fs = 250,
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V6nd_9auth = 251,
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SRC_UNSPEC = 0,
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SRC_UNI = 1,
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TARG_UNI = 2,
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TARG_MULTI = 3,
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Tunitent = 1,
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Tuniproxy = 2,
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Tunirany = 3,
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/* Node constants */
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MAX_MULTICAST_SOLICIT = 3,
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RETRANS_TIMER = 1000,
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};
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typedef struct Ip6hdr Ip6hdr;
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typedef struct Opthdr Opthdr;
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typedef struct Routinghdr Routinghdr;
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typedef struct Fraghdr6 Fraghdr6;
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/* we do this in case there's padding at the end of Ip6hdr */
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#define IPV6HDR \
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uchar vcf[4]; /* version:4, traffic class:8, flow label:20 */\
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uchar ploadlen[2]; /* payload length: packet length - 40 */ \
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uchar proto; /* next header type */ \
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uchar ttl; /* hop limit */ \
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uchar src[IPaddrlen]; \
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uchar dst[IPaddrlen]
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struct Ip6hdr {
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IPV6HDR;
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uchar payload[];
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};
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struct Opthdr { /* unused */
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uchar nexthdr;
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uchar len;
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};
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/*
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* Beware routing header type 0 (loose source routing); see
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* http://www.secdev.org/conf/IPv6_RH_security-csw07.pdf.
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* Type 1 is unused. Type 2 is for MIPv6 (mobile IPv6) filtering
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* against type 0 header.
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*/
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struct Routinghdr { /* unused */
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uchar nexthdr;
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uchar len;
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uchar rtetype;
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uchar segrem;
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};
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struct Fraghdr6 {
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uchar nexthdr;
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uchar res;
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uchar offsetRM[2]; /* Offset, Res, M flag */
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uchar id[4];
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};
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extern uchar v6allnodesN[IPaddrlen];
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extern uchar v6allnodesL[IPaddrlen];
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extern uchar v6allroutersN[IPaddrlen];
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extern uchar v6allroutersL[IPaddrlen];
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extern uchar v6allnodesNmask[IPaddrlen];
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extern uchar v6allnodesLmask[IPaddrlen];
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extern uchar v6solicitednode[IPaddrlen];
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extern uchar v6solicitednodemask[IPaddrlen];
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extern uchar v6Unspecified[IPaddrlen];
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extern uchar v6loopback[IPaddrlen];
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extern uchar v6linklocal[IPaddrlen];
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extern uchar v6linklocalmask[IPaddrlen];
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extern uchar v6multicast[IPaddrlen];
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extern uchar v6multicastmask[IPaddrlen];
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extern int v6llpreflen;
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extern int v6mcpreflen;
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extern int v6snpreflen;
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extern int v6aNpreflen;
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extern int v6aLpreflen;
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void ipv62smcast(uchar *, uchar *);
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void icmpns(Fs *f, uchar* src, int suni, uchar* targ, int tuni, uchar* mac);
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void icmpna(Fs *f, uchar* src, uchar* dst, uchar* targ, uchar* mac, uchar flags);
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void icmpttlexceeded6(Fs *f, Ipifc *ifc, Block *bp);
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void icmppkttoobig6(Fs *f, Ipifc *ifc, Block *bp);
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void icmphostunr6(Fs *f, Ipifc *ifc, Block *bp, int code, int tome);
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