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pkt-gen: fix UDP checksum when IPv6 address ranges are used #990

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pkt-gen: fix UDP checksum when IPv6 address ranges are used #990

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30 changes: 14 additions & 16 deletions apps/pkt-gen/pkt-gen.c
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Original file line number Diff line number Diff line change
Expand Up @@ -917,15 +917,14 @@ update_ip6(struct pkt *pkt, struct targ *t)
struct glob_arg *g = t->g;
struct ip6_hdr ip6;
struct udphdr udp;
uint16_t udp_sum;
uint16_t udp_sum = 0;
uint16_t oaddr, naddr;
uint16_t oport, nport;
uint8_t group;

memcpy(&ip6, &pkt->ipv6.ip, sizeof(ip6));
memcpy(&udp, &pkt->ipv6.udp, sizeof(udp));
do {
udp_sum = 0;
group = g->src_ip.ipv6.sgroup;
naddr = oaddr = ntohs(ip6.ip6_src.s6_addr16[group]);
nport = oport = ntohs(udp.uh_sport);
Expand All @@ -934,29 +933,28 @@ update_ip6(struct pkt *pkt, struct targ *t)
udp.uh_sport = nrand48(t->seed);
naddr = ntohs(ip6.ip6_src.s6_addr16[group]);
nport = ntohs(udp.uh_sport);
udp_sum = new_udp_sum(udp_sum, oaddr, naddr);
udp_sum = new_udp_sum(udp_sum, oport, nport);
break;
}
if (oport < g->src_ip.port1) {
nport = oport + 1;
udp.uh_sport = htons(nport);
udp_sum = new_udp_sum(udp_sum, oport, nport);
break;
}
nport = g->src_ip.port0;
udp.uh_sport = htons(nport);
udp_sum = new_udp_sum(udp_sum, oport, nport);
if (oaddr < ntohs(g->src_ip.ipv6.end.s6_addr16[group])) {
naddr = oaddr + 1;
ip6.ip6_src.s6_addr16[group] = htons(naddr);
udp_sum = new_udp_sum(udp_sum, oaddr, naddr);
break;
}
naddr = ntohs(g->src_ip.ipv6.start.s6_addr16[group]);
ip6.ip6_src.s6_addr16[group] = htons(naddr);

/* update checksums if needed */
if (oaddr != naddr)
udp_sum = cksum_add(~oaddr, naddr);
if (oport != nport)
udp_sum = cksum_add(udp_sum,
cksum_add(~oport, nport));
udp_sum = new_udp_sum(udp_sum, oaddr, naddr);

group = g->dst_ip.ipv6.egroup;
naddr = oaddr = ntohs(ip6.ip6_dst.s6_addr16[group]);
Expand All @@ -966,32 +964,32 @@ update_ip6(struct pkt *pkt, struct targ *t)
udp.uh_dport = nrand48(t->seed);
naddr = ntohs(ip6.ip6_dst.s6_addr16[group]);
nport = ntohs(udp.uh_dport);
udp_sum = new_udp_sum(udp_sum, oaddr, naddr);
udp_sum = new_udp_sum(udp_sum, oport, nport);
break;
}
if (oport < g->dst_ip.port1) {
nport = oport + 1;
udp.uh_dport = htons(nport);
udp_sum = new_udp_sum(udp_sum, oport, nport);
break;
}
nport = g->dst_ip.port0;
udp.uh_dport = htons(nport);
udp_sum = new_udp_sum(udp_sum, oport, nport);
if (oaddr < ntohs(g->dst_ip.ipv6.end.s6_addr16[group])) {
naddr = oaddr + 1;
ip6.ip6_dst.s6_addr16[group] = htons(naddr);
udp_sum = new_udp_sum(udp_sum, oaddr, naddr);
break;
}
naddr = ntohs(g->dst_ip.ipv6.start.s6_addr16[group]);
ip6.ip6_dst.s6_addr16[group] = htons(naddr);
udp_sum = new_udp_sum(udp_sum, oaddr, naddr);
} while (0);
/* update checksums */
if (oaddr != naddr)
udp_sum = cksum_add(udp_sum,
cksum_add(~oaddr, naddr));
if (oport != nport)
udp_sum = cksum_add(udp_sum,
cksum_add(~oport, nport));
if (udp_sum != 0)
udp.uh_sum = ~cksum_add(~udp.uh_sum, udp_sum);
udp.uh_sum = ~cksum_add(~udp.uh_sum, htons(udp_sum));
memcpy(&pkt->ipv6.ip, &ip6, sizeof(ip6));
memcpy(&pkt->ipv6.udp, &udp, sizeof(udp));
}
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