Make "link[N:M]" refer to the 802.11 header for all 802.11 DLT_ values,

[libpcap] / gencode.c

diff --git a/gencode.c b/gencode.c
index 1125b18fd52b023996bc114185c32b4841ed63ae..82748d89e1c5abf1655838b4131e88e6ac05aa8b 100644 (file)
--- a/gencode.c
+++ b/gencode.c
@@ -21,7 +21,7 @@
  */
 #ifndef lint
 static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.241 2005-05-01 19:32:38 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.242 2005-05-02 21:13:08 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -135,6 +135,7 @@ static struct block *root;
  * is relative to.
  */
 enum e_offrel {
+       OR_PACKET,      /* relative to the beginning of the packet */
        OR_LINK,        /* relative to the link-layer header */
        OR_NET,         /* relative to the network-layer header */
        OR_NET_NOSNAP,  /* relative to the network-layer header, with no SNAP header at the link layer */
@@ -665,6 +666,12 @@ gen_ncmp(offrel, offset, size, mask, jtype, reverse, v)
  */
 static int reg_ll_size;
 
+/*
+ * This is the offset of the beginning of the link-layer header.
+ * It's usually 0, except for 802.11 with a fixed-length radio header.
+ */
+static u_int off_ll;
+
 /*
  * This is the offset of the beginning of the MAC-layer header.
  * It's usually 0, except for ATM LANE.
@@ -763,6 +770,11 @@ init_linktype(p)
        off_proto = -1;
        off_payload = -1;
 
+       /*
+        * Also assume it's not 802.11 with a fixed-length radio header.
+        */
+       off_ll = 0;
+
        orig_linktype = -1;
        orig_nl = -1;
 
@@ -925,6 +937,7 @@ init_linktype(p)
                 * XXX - same variable-length header problem; at least
                 * the Prism header is fixed-length.
                 */
+               off_ll = 144;
                off_linktype = 144+24;
                off_nl = 144+32;        /* Prism+802.11+802.2+SNAP */
                off_nl_nosnap = 144+27; /* Prism+802.11+802.2 */
@@ -945,6 +958,7 @@ init_linktype(p)
                 * number at an offset of 4 from the beginning
                 * of the radio header.
                 */
+               off_ll = 64;
                off_linktype = 64+24;
                off_nl = 64+32;         /* Radio+802.11+802.2+SNAP */
                off_nl_nosnap = 64+27;  /* Radio+802.11+802.2 */
@@ -1161,10 +1175,14 @@ gen_load_a(offrel, offset, size)
 
        switch (offrel) {
 
-       case OR_LINK:
+       case OR_PACKET:
                s = gen_load_llrel(offset, size);
                break;
 
+       case OR_LINK:
+               s = gen_load_llrel(off_ll + offset, size);
+               break;
+
        case OR_NET:
                s = gen_load_llrel(off_nl + offset, size);
                break;
@@ -3051,6 +3069,9 @@ gen_host(addr, mask, proto, dir)
        case Q_NETBEUI:
                bpf_error("'netbeui' modifier applied to host");
 
+       case Q_RADIO:
+               bpf_error("'radio' modifier applied to host");
+
        default:
                abort();
        }
@@ -3157,6 +3178,9 @@ gen_host6(addr, mask, proto, dir)
        case Q_NETBEUI:
                bpf_error("'netbeui' modifier applied to host");
 
+       case Q_RADIO:
+               bpf_error("'radio' modifier applied to host");
+
        default:
                abort();
        }
@@ -3464,6 +3488,9 @@ gen_proto_abbrev(proto)
                b1 = gen_linktype(LLCSAP_NETBEUI);
                break;
 
+       case Q_RADIO:
+               bpf_error("'radio' is not a valid protocol type");
+
        default:
                abort();
        }
@@ -4448,6 +4475,9 @@ gen_proto(v, proto, dir)
        case Q_NETBEUI:
                bpf_error("'netbeui proto' is bogus");
 
+       case Q_RADIO:
+               bpf_error("'radio proto' is bogus");
+
        default:
                abort();
                /* NOTREACHED */
@@ -5093,6 +5123,31 @@ gen_load(proto, index, size)
        default:
                bpf_error("unsupported index operation");
 
+       case Q_RADIO:
+               /*
+                * The offset is relative to the beginning of the packet
+                * data, if we have a radio header.  (If we don't, this
+                * is an error.)
+                */
+               if (linktype != DLT_IEEE802_11_RADIO_AVS &&
+                   linktype != DLT_IEEE802_11_RADIO &&
+                   linktype != DLT_PRISM_HEADER)
+                       bpf_error("radio information not present in capture");
+
+               /*
+                * Load into the X register the offset computed into the
+                * register specifed by "index".
+                */
+               s = xfer_to_x(index);
+
+               /*
+                * Load the item at that offset.
+                */
+               tmp = new_stmt(BPF_LD|BPF_IND|size);
+               sappend(s, tmp);
+               sappend(index->s, s);
+               break;
+
        case Q_LINK:
                /*
                 * The offset is relative to the beginning of
@@ -5124,9 +5179,14 @@ gen_load(proto, index, size)
                        s = xfer_to_x(index);
 
                /*
-                * Load the item at the offset we've put in the X register.
+                * Load the item at the sum of the offset we've put in the
+                * X register and the offset of the start of the link
+                * layer header (which is 0 if the radio header is
+                * variable-length; that header length is what we put
+                * into the X register and then added to the index).
                 */
                tmp = new_stmt(BPF_LD|BPF_IND|size);
+               tmp->s.k = off_ll;
                sappend(s, tmp);
                sappend(index->s, s);
                break;