Don't forget to recalculate the IP checksum of the original
IP datagram embedded into ICMP error message. Spotted by: tcpdump 3.7.1 (-vvv) MFC after: 3 days
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parent
290006640b
commit
61a875d706
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=100537
@ -352,7 +352,7 @@ IcmpAliasIn2(struct ip *pip)
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if (ip->ip_p == IPPROTO_UDP || ip->ip_p == IPPROTO_TCP)
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{
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u_short *sptr;
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int accumulate;
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int accumulate, accumulate2;
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struct in_addr original_address;
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u_short original_port;
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@ -368,7 +368,11 @@ IcmpAliasIn2(struct ip *pip)
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accumulate -= *sptr;
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accumulate += ud->uh_sport;
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accumulate -= original_port;
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ADJUST_CHECKSUM(accumulate, ic->icmp_cksum);
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accumulate2 = accumulate;
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accumulate2 += ip->ip_sum;
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ADJUST_CHECKSUM(accumulate, ip->ip_sum);
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accumulate2 -= ip->ip_sum;
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ADJUST_CHECKSUM(accumulate2, ic->icmp_cksum);
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/* Un-alias address in IP header */
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DifferentialChecksum(&pip->ip_sum,
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@ -385,7 +389,7 @@ fragment contained in ICMP data section */
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else if (ip->ip_p == IPPROTO_ICMP)
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{
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u_short *sptr;
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int accumulate;
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int accumulate, accumulate2;
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struct in_addr original_address;
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u_short original_id;
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@ -401,7 +405,11 @@ fragment contained in ICMP data section */
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accumulate -= *sptr;
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accumulate += ic2->icmp_id;
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accumulate -= original_id;
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ADJUST_CHECKSUM(accumulate, ic->icmp_cksum);
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accumulate2 = accumulate;
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accumulate2 += ip->ip_sum;
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ADJUST_CHECKSUM(accumulate, ip->ip_sum);
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accumulate2 -= ip->ip_sum;
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ADJUST_CHECKSUM(accumulate2, ic->icmp_cksum);
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/* Un-alias address in IP header */
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DifferentialChecksum(&pip->ip_sum,
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@ -352,7 +352,7 @@ IcmpAliasIn2(struct ip *pip)
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if (ip->ip_p == IPPROTO_UDP || ip->ip_p == IPPROTO_TCP)
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{
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u_short *sptr;
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int accumulate;
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int accumulate, accumulate2;
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struct in_addr original_address;
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u_short original_port;
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@ -368,7 +368,11 @@ IcmpAliasIn2(struct ip *pip)
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accumulate -= *sptr;
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accumulate += ud->uh_sport;
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accumulate -= original_port;
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ADJUST_CHECKSUM(accumulate, ic->icmp_cksum);
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accumulate2 = accumulate;
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accumulate2 += ip->ip_sum;
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ADJUST_CHECKSUM(accumulate, ip->ip_sum);
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accumulate2 -= ip->ip_sum;
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ADJUST_CHECKSUM(accumulate2, ic->icmp_cksum);
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/* Un-alias address in IP header */
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DifferentialChecksum(&pip->ip_sum,
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@ -385,7 +389,7 @@ fragment contained in ICMP data section */
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else if (ip->ip_p == IPPROTO_ICMP)
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{
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u_short *sptr;
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int accumulate;
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int accumulate, accumulate2;
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struct in_addr original_address;
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u_short original_id;
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@ -401,7 +405,11 @@ fragment contained in ICMP data section */
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accumulate -= *sptr;
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accumulate += ic2->icmp_id;
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accumulate -= original_id;
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ADJUST_CHECKSUM(accumulate, ic->icmp_cksum);
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accumulate2 = accumulate;
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accumulate2 += ip->ip_sum;
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ADJUST_CHECKSUM(accumulate, ip->ip_sum);
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accumulate2 -= ip->ip_sum;
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ADJUST_CHECKSUM(accumulate2, ic->icmp_cksum);
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/* Un-alias address in IP header */
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DifferentialChecksum(&pip->ip_sum,
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