OpenFlow 1.0: Get snapend right for nested frames. [skip ci]

The current and the nested packets can and do have different snapend,
implement and comment that in of10_packet_data_print() to fix an issue
discovered by Francois-Xavier Le Bail.

diff --git a/CHANGES b/CHANGES
index de07436e4468af12c998b909d4103f097735bc6f..75de7b715de0eeaff7a2ecf118b0e6a2f6355d0a 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -14,6 +14,7 @@ Monthday, Month DD, YYYY by gharris and denis
       AppleTalk: Declutter appletalk.h.
       Introduce new ND_LCHECK*() macros to deduplicate more code.
       IEEE 802.11: Simplify handle_action().
+      OpenFlow 1.0: Get snapend right for nested frames.
 
 Monthday, Month DD, YYYY by gharris
   Summary for 4.99.1 tcpdump release (so far!)

diff --git a/print-openflow-1.0.c b/print-openflow-1.0.c
index df57a09a38aa401fc4724c17837e0a5ff029efae..7751f2d90ead0ef24bdf2870359f3fe11932b943 100644 (file)
--- a/print-openflow-1.0.c
+++ b/print-openflow-1.0.c
@@ -1017,7 +1017,19 @@ of10_packet_data_print(netdissect_options *ndo,
        }
        ndo->ndo_vflag -= 3;
        ND_PRINT(", frame decoding below\n");
+       /*
+        * The encapsulated Ethernet frame is not necessarily the last
+        * data of this packet (i.e. there may be more OpenFlow messages
+        * after the current OFPT_PACKET_IN/OFPT_PACKET_OUT message, in
+        * which case the current (outer) packet's snapshot end is not
+        * what ether_print() needs to decode an Ethernet frame nested in
+        * the middle of a TCP payload.
+        */
+       if (!nd_push_snapend(ndo, cp + len))
+               (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC,
+                                 "%s: failed to adjust snapend", __func__);
        ether_print(ndo, cp, len, ND_BYTES_AVAILABLE_AFTER(cp), NULL, NULL);
+       nd_pop_packet_info(ndo);
        ndo->ndo_vflag += 3;
 }