Move the code to generate code to check for a particular linktype in the
Linux cooked header into a routine of its own.
This commit is contained in:
guy
parent
f9b1d9732a
commit
a1e08cec1e
328
gencode.c
328
gencode.c
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@ -21,7 +21,7 @@
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*/
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#ifndef lint
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static const char rcsid[] _U_ =
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"@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.210 2004-10-19 15:55:28 hannes Exp $ (LBL)";
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"@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.211 2004-11-06 22:45:17 guy Exp $ (LBL)";
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#endif
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#ifdef HAVE_CONFIG_H
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@ -165,6 +165,7 @@ static struct block *gen_uncond(int);
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static inline struct block *gen_true(void);
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static inline struct block *gen_false(void);
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static struct block *gen_ether_linktype(int);
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static struct block *gen_linux_sll_linktype(int);
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static struct block *gen_linktype(int);
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static struct block *gen_snap(bpf_u_int32, bpf_u_int32, u_int);
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static struct block *gen_llc(int);
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@ -1259,6 +1260,172 @@ gen_ether_linktype(proto)
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}
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}
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static struct block *
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gen_linux_sll_linktype(proto)
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register int proto;
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{
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struct block *b0, *b1;
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switch (proto) {
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case LLCSAP_IP:
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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b1 = gen_cmp(off_linktype + 2, BPF_H, (bpf_int32)
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((LLCSAP_IP << 8) | LLCSAP_IP));
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gen_and(b0, b1);
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return b1;
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case LLCSAP_ISONS:
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/*
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* OSI protocols always use 802.2 encapsulation.
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* XXX - should we check both the DSAP and the
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* LSAP, like this, or should we check just the
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* DSAP?
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*/
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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b1 = gen_cmp(off_linktype + 2, BPF_H, (bpf_int32)
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((LLCSAP_ISONS << 8) | LLCSAP_ISONS));
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gen_and(b0, b1);
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return b1;
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case LLCSAP_NETBEUI:
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/*
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* NetBEUI always uses 802.2 encapsulation.
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* XXX - should we check both the DSAP and the
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* LSAP, like this, or should we check just the
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* DSAP?
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*/
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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b1 = gen_cmp(off_linktype + 2, BPF_H, (bpf_int32)
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((LLCSAP_NETBEUI << 8) | LLCSAP_NETBEUI));
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gen_and(b0, b1);
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return b1;
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case LLCSAP_IPX:
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/*
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* Ethernet_II frames, which are Ethernet
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* frames with a frame type of ETHERTYPE_IPX;
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*
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* Ethernet_802.3 frames, which have a frame
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* type of LINUX_SLL_P_802_3;
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*
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* Ethernet_802.2 frames, which are 802.3
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* frames with an 802.2 LLC header (i.e, have
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* a frame type of LINUX_SLL_P_802_2) and
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* with the IPX LSAP as the DSAP in the LLC
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* header;
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*
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* Ethernet_SNAP frames, which are 802.3
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* frames with an LLC header and a SNAP
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* header and with an OUI of 0x000000
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* (encapsulated Ethernet) and a protocol
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* ID of ETHERTYPE_IPX in the SNAP header.
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*
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* First, do the checks on LINUX_SLL_P_802_2
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* frames; generate the check for either
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* Ethernet_802.2 or Ethernet_SNAP frames, and
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* then put a check for LINUX_SLL_P_802_2 frames
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* before it.
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*/
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b0 = gen_cmp(off_linktype + 2, BPF_B,
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(bpf_int32)LLCSAP_IPX);
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b1 = gen_snap(0x000000, ETHERTYPE_IPX,
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off_linktype + 2);
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gen_or(b0, b1);
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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gen_and(b0, b1);
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/*
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* Now check for 802.3 frames and OR that with
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* the previous test.
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*/
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_3);
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gen_or(b0, b1);
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/*
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* Now add the check for Ethernet_II frames, and
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* do that before checking for the other frame
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* types.
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*/
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b0 = gen_cmp(off_linktype, BPF_H,
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(bpf_int32)ETHERTYPE_IPX);
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gen_or(b0, b1);
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return b1;
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case ETHERTYPE_ATALK:
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case ETHERTYPE_AARP:
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/*
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* EtherTalk (AppleTalk protocols on Ethernet link
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* layer) may use 802.2 encapsulation.
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*/
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/*
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* Check for 802.2 encapsulation (EtherTalk phase 2?);
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* we check for the 802.2 protocol type in the
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* "Ethernet type" field.
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*/
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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/*
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* 802.2-encapsulated ETHERTYPE_ATALK packets are
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* SNAP packets with an organization code of
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* 0x080007 (Apple, for Appletalk) and a protocol
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* type of ETHERTYPE_ATALK (Appletalk).
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*
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* 802.2-encapsulated ETHERTYPE_AARP packets are
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* SNAP packets with an organization code of
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* 0x000000 (encapsulated Ethernet) and a protocol
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* type of ETHERTYPE_AARP (Appletalk ARP).
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*/
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if (proto == ETHERTYPE_ATALK)
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b1 = gen_snap(0x080007, ETHERTYPE_ATALK,
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off_linktype + 2);
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else /* proto == ETHERTYPE_AARP */
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b1 = gen_snap(0x000000, ETHERTYPE_AARP,
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off_linktype + 2);
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gen_and(b0, b1);
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/*
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* Check for Ethernet encapsulation (Ethertalk
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* phase 1?); we just check for the Ethernet
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* protocol type.
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*/
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b0 = gen_cmp(off_linktype, BPF_H, (bpf_int32)proto);
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gen_or(b0, b1);
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return b1;
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default:
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if (proto <= ETHERMTU) {
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/*
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* This is an LLC SAP value, so the frames
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* that match would be 802.2 frames.
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* Check for the 802.2 protocol type
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* in the "Ethernet type" field, and
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* then check the DSAP.
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*/
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b0 = gen_cmp(off_linktype, BPF_H,
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LINUX_SLL_P_802_2);
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b1 = gen_cmp(off_linktype + 2, BPF_B,
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(bpf_int32)proto);
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gen_and(b0, b1);
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return b1;
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} else {
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/*
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* This is an Ethernet type, so compare
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* the length/type field with it (if
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* the frame is an 802.2 frame, the length
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* field will be <= ETHERMTU, and, as
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* "proto" is > ETHERMTU, this test
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* will fail and the frame won't match,
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* which is what we want).
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*/
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return gen_cmp(off_linktype, BPF_H,
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(bpf_int32)proto);
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}
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}
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}
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static struct block *
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gen_linktype(proto)
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register int proto;
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@ -1333,164 +1500,7 @@ gen_linktype(proto)
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}
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case DLT_LINUX_SLL:
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switch (proto) {
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case LLCSAP_IP:
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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b1 = gen_cmp(off_linktype + 2, BPF_H, (bpf_int32)
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((LLCSAP_IP << 8) | LLCSAP_IP));
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gen_and(b0, b1);
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return b1;
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case LLCSAP_ISONS:
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/*
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* OSI protocols always use 802.2 encapsulation.
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* XXX - should we check both the DSAP and the
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* LSAP, like this, or should we check just the
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* DSAP?
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*/
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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b1 = gen_cmp(off_linktype + 2, BPF_H, (bpf_int32)
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((LLCSAP_ISONS << 8) | LLCSAP_ISONS));
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gen_and(b0, b1);
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return b1;
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case LLCSAP_NETBEUI:
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/*
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* NetBEUI always uses 802.2 encapsulation.
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* XXX - should we check both the DSAP and the
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* LSAP, like this, or should we check just the
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* DSAP?
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*/
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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b1 = gen_cmp(off_linktype + 2, BPF_H, (bpf_int32)
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((LLCSAP_NETBEUI << 8) | LLCSAP_NETBEUI));
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gen_and(b0, b1);
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return b1;
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case LLCSAP_IPX:
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/*
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* Ethernet_II frames, which are Ethernet
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* frames with a frame type of ETHERTYPE_IPX;
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*
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* Ethernet_802.3 frames, which have a frame
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* type of LINUX_SLL_P_802_3;
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*
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* Ethernet_802.2 frames, which are 802.3
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* frames with an 802.2 LLC header (i.e, have
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* a frame type of LINUX_SLL_P_802_2) and
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* with the IPX LSAP as the DSAP in the LLC
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* header;
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*
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* Ethernet_SNAP frames, which are 802.3
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* frames with an LLC header and a SNAP
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* header and with an OUI of 0x000000
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* (encapsulated Ethernet) and a protocol
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* ID of ETHERTYPE_IPX in the SNAP header.
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*
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* First, do the checks on LINUX_SLL_P_802_2
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* frames; generate the check for either
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* Ethernet_802.2 or Ethernet_SNAP frames, and
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* then put a check for LINUX_SLL_P_802_2 frames
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* before it.
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*/
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b0 = gen_cmp(off_linktype + 2, BPF_B,
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(bpf_int32)LLCSAP_IPX);
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b1 = gen_snap(0x000000, ETHERTYPE_IPX,
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off_linktype + 2);
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gen_or(b0, b1);
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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gen_and(b0, b1);
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/*
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* Now check for 802.3 frames and OR that with
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* the previous test.
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*/
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_3);
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gen_or(b0, b1);
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/*
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* Now add the check for Ethernet_II frames, and
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* do that before checking for the other frame
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* types.
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*/
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b0 = gen_cmp(off_linktype, BPF_H,
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(bpf_int32)ETHERTYPE_IPX);
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gen_or(b0, b1);
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return b1;
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case ETHERTYPE_ATALK:
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case ETHERTYPE_AARP:
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/*
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* EtherTalk (AppleTalk protocols on Ethernet link
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* layer) may use 802.2 encapsulation.
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*/
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/*
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* Check for 802.2 encapsulation (EtherTalk phase 2?);
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* we check for the 802.2 protocol type in the
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* "Ethernet type" field.
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*/
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b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
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/*
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* 802.2-encapsulated ETHERTYPE_ATALK packets are
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* SNAP packets with an organization code of
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* 0x080007 (Apple, for Appletalk) and a protocol
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* type of ETHERTYPE_ATALK (Appletalk).
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*
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* 802.2-encapsulated ETHERTYPE_AARP packets are
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* SNAP packets with an organization code of
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* 0x000000 (encapsulated Ethernet) and a protocol
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* type of ETHERTYPE_AARP (Appletalk ARP).
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*/
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if (proto == ETHERTYPE_ATALK)
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b1 = gen_snap(0x080007, ETHERTYPE_ATALK,
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off_linktype + 2);
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else /* proto == ETHERTYPE_AARP */
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b1 = gen_snap(0x000000, ETHERTYPE_AARP,
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off_linktype + 2);
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gen_and(b0, b1);
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/*
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* Check for Ethernet encapsulation (Ethertalk
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* phase 1?); we just check for the Ethernet
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* protocol type.
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*/
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b0 = gen_cmp(off_linktype, BPF_H, (bpf_int32)proto);
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gen_or(b0, b1);
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return b1;
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default:
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if (proto <= ETHERMTU) {
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/*
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* This is an LLC SAP value, so the frames
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* that match would be 802.2 frames.
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* Check for the 802.2 protocol type
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* in the "Ethernet type" field, and
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* then check the DSAP.
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*/
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b0 = gen_cmp(off_linktype, BPF_H,
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LINUX_SLL_P_802_2);
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b1 = gen_cmp(off_linktype + 2, BPF_B,
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(bpf_int32)proto);
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gen_and(b0, b1);
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return b1;
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} else {
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/*
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* This is an Ethernet type, so compare
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* the length/type field with it (if
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* the frame is an 802.2 frame, the length
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* field will be <= ETHERMTU, and, as
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* "proto" is > ETHERMTU, this test
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* will fail and the frame won't match,
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* which is what we want).
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*/
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return gen_cmp(off_linktype, BPF_H,
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(bpf_int32)proto);
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}
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}
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return gen_linux_sll_linktype(proto);
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/*NOTREACHED*/
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break;
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