Changeset df338b3 for lib/trace.c

Timestamp:

02/20/06 13:52:09 (16 years ago)

Author:

Perry Lorier <perry@…>

Branches:

4.0.1-hotfixes, cachetimestamps, develop, dpdk-ndag, etsilive, getfragoff, help, libtrace4, master, ndag_format, pfring, rc-4.0.1, rc-4.0.2, rc-4.0.3, rc-4.0.4, ringdecrementfix, ringperformance, ringtimestampfixes

Children:

8ee7caa

Parents:

548a9c2

Message:

Major restructuring of format_pcap

File:

• lib/trace.c (modified) (5 diffs)

lib/trace.c

@@ -120 +120 @@
 #define MAXOPTS 1024
 
-#if HAVE_BPF
-/* A type encapsulating a bpf filter
- * This type covers the compiled bpf filter, as well as the original filter
- * string
- *
- */
-struct libtrace_filter_t {
-        struct bpf_insn *filter;
-        char * filterstring;
-};
-#endif
 
 struct trace_err_t trace_err;
@@ -405 +394 @@
 int trace_start(struct libtrace_t *libtrace)
 {
+        assert(libtrace);
         if (libtrace->format->start_input) {
                 int ret=libtrace->format->start_input(libtrace);
@@ -543 +533 @@
                 do {
                         packet->size=libtrace->format->read_packet(libtrace,packet);
-                        if (packet->size==-1)
+                        if (packet->size==-1 || packet->size==0)
                                 return packet->size;
                         if (libtrace->filter) {
@@ -1252 +1242 @@
         struct libtrace_filter_t *filter = malloc(sizeof(struct libtrace_filter_t));
         filter->filterstring = strdup(filterstring);
-        filter->filter = 0;
+        filter->flag = 0;
         return filter;
 #else
         fprintf(stderr,"This version of libtrace does not have bpf filter support\n");
         return 0;
+#endif
+}
+
+/* compile a bpf filter, now we know what trace it's on
+ * @internal
+ *
+ * @returns -1 on error, 0 on success
+ */
+int trace_bpf_compile(libtrace_filter_t *filter,
+                const libtrace_packet_t *packet ) {
+#if HAVE_BPF
+        void *linkptr = 0;
+        assert(filter);
+
+        /* If this isn't a real packet, then fail */
+        linkptr = trace_get_link(packet);
+        if (!linkptr) {
+                return -1;
+        }
+        
+        if (filter->filterstring && ! filter->flag) {
+                pcap_t *pcap;
+                pcap=(pcap_t *)pcap_open_dead(
+                                libtrace_to_pcap_dlt(trace_get_link_type(packet)),
+                                1500);
+                /* build filter */
+                if (pcap_compile( pcap, &filter->filter, filter->filterstring, 
+                                        1, 0)) {
+                        pcap_close(pcap);
+                        return -1;
+                }
+                pcap_close(pcap);
+                filter->flag=1;
+        }
+        return 0;
+#else
+        assert(!"This should never be called when BPF not enabled");
 #endif
 }
@@ -1277 +1304 @@
                 return 0;
         }
+
+        /* We need to compile it now, because before we didn't know what the 
+         * link type was
+         */
+        trace_bpf_compile(filter,packet);
         
         clen = trace_get_capture_length(packet);
-        
-
-        if (filter->filterstring && ! filter->filter) {
-                pcap_t *pcap;
-                struct bpf_program bpfprog;
-                pcap=(pcap_t *)pcap_open_dead(
-                                libtrace_to_pcap_dlt(trace_get_link_type(packet)),
-                                1500);
-                /* build filter */
-                if (pcap_compile( pcap, &bpfprog, filter->filterstring, 1, 0)) {
-                        printf("bpf compilation error: %s: %s\n", 
-                                pcap_geterr(pcap),filter->filterstring);
-                        assert(0);
-                }
-                pcap_close(pcap);
-                filter->filter = bpfprog.bf_insns;      
-        }
-
-        assert(filter->filter);
-        return bpf_filter(filter->filter, linkptr, clen, clen);
+
+        assert(filter->flag);
+        return bpf_filter(filter->filter.bf_insns, linkptr, clen, clen);
 #else
         fprintf(stderr,"This version of libtrace does not have bpf filter support\n");