appneta#190 don't process frags for chksum_fix (appneta#294)

baigubulu · Feb 28, 2017 · e9b133e · e9b133e
1 parent d237106
commit e9b133e
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diff --git a/docs/CHANGELOG b/docs/CHANGELOG
@@ -7,6 +7,7 @@
     - Add protection against packet drift by Guillaume Scott (#268)
     - Include Travis-CI build support by Ilya Shipitsin (#264) (#285)
     - First and last packet times in --stats output (#239)
+    - tcprewrite fix checksum properly for fragmented packets (#190)
 
 11/19/2016 Version 4.1.2
     - Fix compilation with musl C library (#260)

diff --git a/src/tcpedit/edit_packet.c b/src/tcpedit/edit_packet.c
@@ -63,7 +63,8 @@ fix_ipv4_checksums(tcpedit_t *tcpedit, struct pcap_pkthdr *pkthdr, ipv4_hdr_t *i
 
 
     /* calc the L4 checksum if we have the whole packet && not a frag or first frag */
-    if (pkthdr->caplen == pkthdr->len && (htons(ip_hdr->ip_off) & IP_OFFMASK) == 0) {
+    if (pkthdr->caplen == pkthdr->len &&
+            (htons(ip_hdr->ip_off) & (IP_MF | IP_OFFMASK)) == 0) {
         ret1 = do_checksum(tcpedit, (u_char *) ip_hdr, 
                 ip_hdr->ip_p, ntohs(ip_hdr->ip_len) - (ip_hdr->ip_hl << 2));
         if (ret1 < 0)