devbridge: fix mss clamping
- use protocol constants from ip/ip.h and ip/ipv6.h - support mss clamping for ipv6 - fix padding bug on 64 bit machines (can't use sizeof(Tcphdr))
This commit is contained in:
cinap_lenrek
parent
0affe02b61
commit
520c938f0b
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@ -1,5 +1,5 @@
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/*
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* IPv4 Ethernet bridge
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* IP Ethernet bridge
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*/
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#include "u.h"
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#include "../port/lib.h"
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@ -7,13 +7,13 @@
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#include "dat.h"
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#include "fns.h"
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#include "../ip/ip.h"
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#include "../ip/ipv6.h"
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#include "../port/netif.h"
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#include "../port/error.h"
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typedef struct Bridge Bridge;
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typedef struct Port Port;
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typedef struct Centry Centry;
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typedef struct Iphdr Iphdr;
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typedef struct Tcphdr Tcphdr;
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enum
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@ -138,27 +138,12 @@ struct Port
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};
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enum {
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IP_TCPPROTO = 6,
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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, /* Mean segment size */
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SYN = 0x02, /* Pkt. is synchronise */
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IPHDR = 20, /* sizeof(Iphdr) */
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};
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struct Iphdr
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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]; /* ip->identification */
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uchar frag[2]; /* Fragment information */
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uchar ttl; /* Time to live */
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uchar proto; /* Protocol */
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uchar cksum[2]; /* Header checksum */
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uchar src[4]; /* IP source */
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uchar dst[4]; /* IP destination */
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TCPHDR = 20,
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};
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struct Tcphdr
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@ -864,34 +849,38 @@ static void
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tcpmsshack(Etherpkt *epkt, int n)
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{
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int hl, optlen;
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Iphdr *iphdr;
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Tcphdr *tcphdr;
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ulong mss, cksum;
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uchar *optr;
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/* ignore non-ipv4 packets */
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if(nhgets(epkt->type) != ETIP4)
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switch(nhgets(epkt->type)){
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case ETIP4:
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case ETIP6:
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break;
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default:
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return;
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iphdr = (Iphdr*)(epkt->data);
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}
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n -= ETHERHDRSIZE;
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if(n < IPHDR)
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if(n < 1)
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return;
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/* ignore bad packets */
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if(iphdr->vihl != (IP_VER4|IP_HLEN4)) {
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hl = (iphdr->vihl&0xF)<<2;
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if((iphdr->vihl&0xF0) != IP_VER4 || hl < (IP_HLEN4<<2))
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switch(epkt->data[0]&0xF0){
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case IP_VER4:
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hl = (epkt->data[0]&15)<<2;
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if(n < hl+TCPHDR || hl < IP4HDR || epkt->data[9] != TCP)
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return;
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} else
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hl = IP_HLEN4<<2;
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/* ignore non-tcp packets */
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if(iphdr->proto != IP_TCPPROTO)
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n -= hl;
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tcphdr = (Tcphdr*)(epkt->data + hl);
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break;
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case IP_VER6:
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if(n < IP6HDR+TCPHDR || epkt->data[6] != TCP)
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return;
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n -= IP6HDR;
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tcphdr = (Tcphdr*)(epkt->data + IP6HDR);
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break;
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default:
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return;
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n -= hl;
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if(n < sizeof(Tcphdr))
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return;
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tcphdr = (Tcphdr*)((uchar*)(iphdr) + hl);
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}
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// MSS can only appear in SYN packet
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if(!(tcphdr->flag[1] & SYN))
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return;
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@ -900,8 +889,8 @@ tcpmsshack(Etherpkt *epkt, int n)
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return;
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// check for MSS option
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optr = (uchar*)tcphdr + sizeof(Tcphdr);
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n = hl - sizeof(Tcphdr);
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optr = (uchar*)tcphdr + TCPHDR;
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n = hl - TCPHDR;
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for(;;) {
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if(n <= 0 || *optr == EOLOPT)
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return;
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@ -922,10 +911,11 @@ tcpmsshack(Etherpkt *epkt, int n)
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mss = nhgets(optr+2);
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if(mss <= TcpMssMax)
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return;
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// fit checksum
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cksum = nhgets(tcphdr->cksum);
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if(optr-(uchar*)tcphdr & 1) {
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print("tcpmsshack: odd alignment!\n");
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// print("tcpmsshack: odd alignment!\n");
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// odd alignments are a pain
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cksum += nhgets(optr+1);
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cksum -= (optr[1]<<8)|(TcpMssMax>>8);
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@ -1028,7 +1018,7 @@ etherread(void *a)
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static int
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fragment(Etherpkt *epkt, int n)
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{
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Iphdr *iphdr;
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Ip4hdr *iphdr;
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if(n <= TunnelMtu)
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return 0;
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@ -1036,14 +1026,14 @@ fragment(Etherpkt *epkt, int n)
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/* ignore non-ipv4 packets */
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if(nhgets(epkt->type) != ETIP4)
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return 0;
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iphdr = (Iphdr*)(epkt->data);
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iphdr = (Ip4hdr*)(epkt->data);
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n -= ETHERHDRSIZE;
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/*
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* ignore: IP runt packets, bad packets (I don't handle IP
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* options for the moment), packets with don't-fragment set,
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* and short blocks.
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*/
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if(n < IPHDR || iphdr->vihl != (IP_VER4|IP_HLEN4) ||
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if(n < IP4HDR || iphdr->vihl != (IP_VER4|IP_HLEN4) ||
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iphdr->frag[0] & (IP_DF>>8) || nhgets(iphdr->length) > n)
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return 0;
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@ -1053,7 +1043,7 @@ fragment(Etherpkt *epkt, int n)
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static void
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etherwrite(Port *port, Block *bp)
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{
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Iphdr *eh, *feh;
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Ip4hdr *eh, *feh;
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Etherpkt *epkt;
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int n, lid, len, seglen, dlen, blklen, mf;
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Block *nb;
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@ -1075,26 +1065,26 @@ etherwrite(Port *port, Block *bp)
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return;
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}
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seglen = (TunnelMtu - ETHERHDRSIZE - IPHDR) & ~7;
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eh = (Iphdr*)(epkt->data);
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seglen = (TunnelMtu - ETHERHDRSIZE - IP4HDR) & ~7;
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eh = (Ip4hdr*)(epkt->data);
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len = nhgets(eh->length);
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frag = nhgets(eh->frag);
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mf = frag & IP_MF;
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frag <<= 3;
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dlen = len - IPHDR;
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dlen = len - IP4HDR;
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lid = nhgets(eh->id);
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bp->rp += ETHERHDRSIZE+IPHDR;
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bp->rp += ETHERHDRSIZE+IP4HDR;
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if(0)
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print("seglen=%d, dlen=%d, mf=%x, frag=%d\n",
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seglen, dlen, mf, frag);
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for(fragoff = 0; fragoff < dlen; fragoff += seglen) {
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nb = allocb(ETHERHDRSIZE+IPHDR+seglen);
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nb = allocb(ETHERHDRSIZE+IP4HDR+seglen);
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feh = (Iphdr*)(nb->wp+ETHERHDRSIZE);
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feh = (Ip4hdr*)(nb->wp+ETHERHDRSIZE);
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memmove(nb->wp, epkt, ETHERHDRSIZE+IPHDR);
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nb->wp += ETHERHDRSIZE+IPHDR;
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memmove(nb->wp, epkt, ETHERHDRSIZE+IP4HDR);
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nb->wp += ETHERHDRSIZE+IP4HDR;
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if((fragoff + seglen) >= dlen) {
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seglen = dlen - fragoff;
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@ -1103,7 +1093,7 @@ etherwrite(Port *port, Block *bp)
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else
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hnputs(feh->frag, (frag+fragoff>>3) | IP_MF);
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hnputs(feh->length, seglen + IPHDR);
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hnputs(feh->length, seglen + IP4HDR);
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hnputs(feh->id, lid);
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if(seglen){
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@ -79,6 +79,7 @@ trap.$O: ../port/systab.h
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devpipe.$O: ../port/netif.h
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netif.$O: ../port/netif.h
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devuart.$O: ../port/netif.h
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devbridge.$O: ../port/netif.h ../ip/ip.h ../ip/ipv6.h
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devdraw.$O: screen.h /sys/include/draw.h /sys/include/memdraw.h /sys/include/memlayer.h /sys/include/cursor.h
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devmouse.$O: screen.h /sys/include/draw.h /sys/include/memdraw.h /sys/include/cursor.h
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swcursor.$O: screen.h /sys/include/draw.h /sys/include/memdraw.h /sys/include/cursor.h
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