#include "pcap/sll.h"
#include "pcap/ipnet.h"
#include "arcnet.h"
+#if defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
+#include <linux/if_packet.h>
+#include <linux/filter.h>
+#endif
#ifdef HAVE_NET_PFVAR_H
#include <sys/socket.h>
#include <net/if.h>
}
/*
- * generate command for inbound/outbound. It's here so we can
- * make it link-type specific. 'dir' = 0 implies "inbound",
- * = 1 implies "outbound".
+ * Filter on inbound (dir == 0) or outbound (dir == 1) traffic.
+ * Outbound traffic is sent by this machine, while inbound traffic is
+ * sent by a remote machine (and may include packets destined for a
+ * unicast or multicast link-layer address we are not subscribing to).
+ * These are the same definitions implemented by pcap_setdirection().
+ * Capturing only unicast traffic destined for this host is probably
+ * better accomplished using a higher-layer filter.
*/
struct block *
gen_inbound(dir)
break;
case DLT_LINUX_SLL:
- if (dir) {
- /*
- * Match packets sent by this machine.
- */
- b0 = gen_cmp(OR_LINK, 0, BPF_H, LINUX_SLL_OUTGOING);
- } else {
- /*
- * Match packets sent to this machine.
- * (No broadcast or multicast packets, or
- * packets sent to some other machine and
- * received promiscuously.)
- *
- * XXX - packets sent to other machines probably
- * shouldn't be matched, but what about broadcast
- * or multicast packets we received?
- */
- b0 = gen_cmp(OR_LINK, 0, BPF_H, LINUX_SLL_HOST);
+ /* match outgoing packets */
+ b0 = gen_cmp(OR_LINK, 0, BPF_H, LINUX_SLL_OUTGOING);
+ if (!dir) {
+ /* to filter on inbound traffic, invert the match */
+ gen_not(b0);
}
break;
break;
default:
+#if defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
+ /* match outgoing packets */
+ b0 = gen_cmp(OR_LINK, SKF_AD_OFF + SKF_AD_PKTTYPE, BPF_H,
+ PACKET_OUTGOING);
+ if (!dir) {
+ /* to filter on inbound traffic, invert the match */
+ gen_not(b0);
+ }
+#else /* defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
bpf_error("inbound/outbound not supported on linktype %d",
linktype);
b0 = NULL;
/* NOTREACHED */
+#endif /* defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
}
return (b0);
}
* header.
*/
p->k -= SLL_HDR_LEN;
+ } else if (p->k == 0) {
+ /*
+ * It's the packet type field; map it to the special magic
+ * kernel offset for that field.
+ */
+ p->k = SKF_AD_OFF + SKF_AD_PKTTYPE;
} else if (p->k == 14) {
/*
* It's the protocol field; map it to the special magic
* kernel offset for that field.
*/
p->k = SKF_AD_OFF + SKF_AD_PROTOCOL;
- } else {
+ } else if ((bpf_int32)(p->k) > 0) {
/*
* It's within the header, but it's not one of those
* fields; we can't do that in the kernel, so punt