ICMP BPF filter

- Fix BPF filter for ICMPv6 and use shorter form
- Add tests for ICMP and ICMP6

src/bpft.c

@@ -86,7 +86,7 @@ void prepare_bpft(void)
     else
         len += text_add(&bpfl, "("); /* ( transports ...  */
     if (wanticmp) {
-        len += text_add(&bpfl, " ( ip proto 1 or ip proto 58 ) or");
+        len += text_add(&bpfl, " ( icmp or icmp6 ) or");
     }
     if (wantfrags) {
         len += text_add(&bpfl, " ( ip[6:2] & 0x1fff != 0 or ip6[6] = 44 ) or");

src/test/Makefile.am

@@ -16,11 +16,12 @@ CLEANFILES = test*.log test*.trs \
   test13.out \
   test14.out \
   test_regex_match.out \
-  edns.out
+  edns.out \
+  test_icmp.out
 
 TESTS = test1.sh test2.sh test3.sh test4.sh test5.sh test6.sh test7.sh \
   test8.sh test9.sh test10.sh test11.sh test12.sh test13.sh test14.sh \
-  test_regex_match.sh test_edns.sh
+  test_regex_match.sh test_edns.sh test_icmp.sh
 
 EXTRA_DIST = $(TESTS) \
   dns.gold dns.pcap \
@@ -36,4 +37,5 @@ EXTRA_DIST = $(TESTS) \
   dns6.pcap test10.gold \
   test14.gold \
   test_regex_match.gold \
-  edns.pcap edns.gold
+  edns.pcap edns.gold \
+  gen_icmp.py icmp.pcap icmp.gold

src/test/gen_icmp.py

@@ -0,0 +1,10 @@
+import sys
+from scapy.all import *
+
+pcap = sys.argv[1]
+
+pkts = []
+pkts.append(Ether()/IPv6(dst="2001:db8:dead::1")/ICMPv6DestUnreach())
+pkts.append(Ether()/IP(dst="0.0.0.0")/ICMP(type=3))
+
+wrpcap(pcap, pkts)

src/test/icmp.gold

@@ -0,0 +1,4 @@
+[48] 2024-09-10 08:52:52.252793 [#0 icmp.pcap 4095] \
+	[fd00::242:ac11:9].0 [2001:db8:dead::1].0 
+[28] 2024-09-10 08:52:52.253461 [#1 icmp.pcap 4095] \
+	[172.17.0.9].0 [0.0.0.0].0 

src/test/test_icmp.sh

@@ -0,0 +1,11 @@
+#!/bin/sh -xe
+
+test -e icmp.pcap || ln -s "$srcdir/icmp.pcap" icmp.pcap
+
+../dnscap -g -I -r icmp.pcap 2>test_icmp.out
+
+mv test_icmp.out test_icmp.out.old
+grep -v "^libgcov profiling error:" test_icmp.out.old > test_icmp.out
+rm test_icmp.out.old
+
+diff test_icmp.out "$srcdir/icmp.gold"