path: root/pcap-dlpi.c
diff options
authorguy <guy>2000-09-17 04:04:36 +0000
committerguy <guy>2000-09-17 04:04:36 +0000
commit781fae35715227add96c7acbfdfc04711c285bde (patch)
tree344180bec293a8ab98235f738f9e859e4e65e37a /pcap-dlpi.c
parent74ab49bec1f5d0ba7e41b395b1ddb6df8f2e2298 (diff)
Introduce a set of PCAP_ENCAP_ codes to specify packet encapsulations.
For those PCAP_ENCAP_ codes corresponding to DLT_ codes that are (believed to be) the same in all BSDs, the PCAP_ENCAP_ codes have the same values as the corresponding DLT_ codes. For those PCAP_ENCAP_ codes corresponding to DLT_ codes that were added in libpcap 0.5 as "non-kernel" DLT_ codes, or had their values changed in libpcap 0.5 in order to cope with the fact that those DLT_ codes have different values in different systems, the PCAP_ENCAP_ codes have the same values as the corresponding DLT_ codes. We add some additional PCAP_ENCAP_ codes to handle IEEE 802.11 (which currently has its link-layer information turned into an Ethernet header by at least some of the BSDs, but John Hawkinson at MIT wants to add a DLT_ value for 802.11 and pass up the full link-layer header) and the Classical IP encapsulation for ATM on Linux (which isn't always the same as DLT_ATM_RFC1483, from what I can tell, alas). "pcap-bpf.c" maps DLT_ codes to PCAP_ENCAP_ codes, so as not to supply to libpcap's callers any DLT_ codes other than the ones that have the same values on all platforms; it supplies PCAP_ENCAP_ codes for all others. In libpcap's "bpf/net/bpf.h", we define the DLT_ values that aren't the same on all platforms with the new values starting at 100 (to keep them out of the way of the values various BSDs might assign to them), as we did in 0.5, but do so only if they're not already defined; platforms with <net/bpf.h> headers that come with the kernel (e.g., the BSDs) should define them with the values that they have always had on that platform, *not* with the values we used in 0.5. (Code using this version of libpcap should check for the new PCAP_ENCAP_ codes; those are given the values that the corresponding DLT_ values had in 0.5, so code that checks for them will handle 0.5 libpcap files correctly even if the platform defines DLT_RAW, say, as something other than 101. If that code also checks for DLT_RAW - which means it can't just use a switch statement, as DLT_RAW might be defined as 101 if the platform doesn't itself define DLT_RAW with some other value - then it will also handle old DLT_RAW captures, as long as they were made on the same platform or on another platform that used the same value for DLT_RAW. It can't handle captures from a platform that uses that value for another DLT_ code, but that's always been the case, and isn't easily fixable.) The intent here is to decouple the values that are returned by "pcap_datalink()" and put into the header of tcpdump/libpcap save files from the DLT_ values returned by BIOCGDLT in BSD kernels, allowing the BSDs to assign values to DLT_ codes, in their kernels, as they choose, without creating more incompatibilities between tcpdump/libpcap save files from different platforms.
Diffstat (limited to 'pcap-dlpi.c')
1 files changed, 4 insertions, 4 deletions
diff --git a/pcap-dlpi.c b/pcap-dlpi.c
index 958caa5..8337dbf 100644
--- a/pcap-dlpi.c
+++ b/pcap-dlpi.c
@@ -38,7 +38,7 @@
#ifndef lint
static const char rcsid[] =
- "@(#) $Header: /tcpdump/master/libpcap/pcap-dlpi.c,v 1.59 2000-08-13 06:56:05 guy Exp $ (LBL)";
+ "@(#) $Header: /tcpdump/master/libpcap/pcap-dlpi.c,v 1.60 2000-09-17 04:04:37 guy Exp $ (LBL)";
@@ -439,17 +439,17 @@ pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
case DL_ETHER:
- p->linktype = DLT_EN10MB;
+ p->linktype = PCAP_ENCAP_ETHERNET;
p->offset = 2;
case DL_FDDI:
- p->linktype = DLT_FDDI;
+ p->linktype = PCAP_ENCAP_FDDI;
p->offset = 3;
- snprintf(ebuf, PCAP_ERRBUF_SIZE, "unknown mac type 0x%lu",
+ snprintf(ebuf, PCAP_ERRBUF_SIZE, "unknown mac type %lu",
goto bad;