diff options
Diffstat (limited to 'lib/libalias')
| -rw-r--r-- | lib/libalias/alias.c | 34 |
1 files changed, 22 insertions, 12 deletions
diff --git a/lib/libalias/alias.c b/lib/libalias/alias.c index e0e5e7c..7689e90 100644 --- a/lib/libalias/alias.c +++ b/lib/libalias/alias.c @@ -539,12 +539,17 @@ IcmpAliasOut2(struct ip *pip) accumulate -= alias_port; ADJUST_CHECKSUM(accumulate, ic->icmp_cksum) -/* Alias address in IP header */ - DifferentialChecksum(&pip->ip_sum, - (u_short *) &alias_address, - (u_short *) &pip->ip_src, - 2); - pip->ip_src = alias_address; +/* + * Alias address in IP header if it comes from the host + * the original TCP/UDP packet was destined for. + */ + if (pip->ip_src.s_addr == ip->ip_dst.s_addr) { + DifferentialChecksum(&pip->ip_sum, + (u_short *) &alias_address, + (u_short *) &pip->ip_src, + 2); + pip->ip_src = alias_address; + } /* Alias address and port number of original IP packet fragment contained in ICMP data section */ @@ -572,12 +577,17 @@ fragment contained in ICMP data section */ accumulate -= alias_id; ADJUST_CHECKSUM(accumulate, ic->icmp_cksum) -/* Alias address in IP header */ - DifferentialChecksum(&pip->ip_sum, - (u_short *) &alias_address, - (u_short *) &pip->ip_src, - 2); - pip->ip_src = alias_address; +/* + * Alias address in IP header if it comes from the host + * the original ICMP message was destined for. + */ + if (pip->ip_src.s_addr == ip->ip_dst.s_addr) { + DifferentialChecksum(&pip->ip_sum, + (u_short *) &alias_address, + (u_short *) &pip->ip_src, + 2); + pip->ip_src = alias_address; + } /* Alias address of original IP packet and sequence number of embedded ICMP datagram */ |
