Working capdiff

src/cap_utils.c

@@ -5,19 +5,30 @@ void cap_load(struct cap_file *cf, char* filename) {
     perror("Unable to open file");
     exit(EXIT_FAILURE);
   }
-
+  cf->filename = filename;
   fseek(cf->fd, 0, SEEK_END);
   cf->sz = ftell(cf->fd);
   fseek(cf->fd, 0, SEEK_SET);
+
+  cf->sz_obj = cf->sz / sizeof(struct buffer_packet);
 }
 
 void cap_next_bp(struct cap_file *cf, struct buffer_packet* bp) {
   fread(bp, sizeof(struct buffer_packet), 1, cf->fd);
 }
 
-void cap_peek_bp(struct cap_file *cf, struct buffer_packet* bp) {
+void cap_npeek_bp(struct cap_file *cf, int c, struct buffer_packet* bp) {
+  //fprintf(stdout, "c: %d, current pos: %ld, ", c, ftell(cf->fd));
+
+  ssize_t cbytes = c*sizeof(struct buffer_packet);
+  fseek(cf->fd, cbytes, SEEK_CUR);
   size_t n = fread(bp, sizeof(struct buffer_packet), 1, cf->fd);
-  fseek(cf->fd, -n, SEEK_CUR);
+  fseek(cf->fd, -(n*sizeof(struct buffer_packet) + cbytes), SEEK_CUR);
+  //fprintf(stdout, "cbytes: %ld, n: %ld, final pos: %ld\n", cbytes, n, ftell(cf->fd));
+}
+
+void cap_peek_bp(struct cap_file *cf, struct buffer_packet* bp) {
+  cap_npeek_bp(cf, 0, bp);
 }
 
 size_t cap_count_bp(struct cap_file *cf) {

src/cap_utils.h

@@ -6,11 +6,14 @@
 
 struct cap_file {
   FILE *fd;
+  char* filename;
   size_t sz;
+  size_t sz_obj;
 };
 
 void cap_load(struct cap_file *cf, char* filename);
 void cap_next_bp(struct cap_file *cf, struct buffer_packet* bp);
 void cap_peek_bp(struct cap_file *cf, struct buffer_packet* bp);
+void cap_npeek_bp(struct cap_file *cf, int c, struct buffer_packet* bp);
 size_t cap_count_bp(struct cap_file *cf);
 void cap_unload(struct cap_file *cf);

src/capdiff.c

@@ -3,12 +3,63 @@
 #include "cap_utils.h"
 #include "packet.h"
 
+#define MAX_PKTS_TO_CHECK_FOR_DROP 10
+
+uint8_t are_packets_equal(struct buffer_packet bpread[]) {
+  size_t s1 = bpread[0].ip.ap.fmt.headers.size, s2 = bpread[1].ip.ap.fmt.headers.size;
+  if (s1 != s2) return 0;
+
+  for (size_t idx = sizeof(bpread[0].ip.ap.fmt.headers) + sizeof(bpread[0].ip.ap.fmt.content.clear) - sizeof(char); idx < s1; idx++) {
+    char e1 = (&bpread[0].ip.ap.raw)[idx], e2 = (&bpread[1].ip.ap.raw)[idx];
+    if (e1 != e2) return 0;
+  }
+
+  return 1;
+}
+
+enum pkt_reconstruct_res { PREC_SAME, PREC_DROP, PREC_FAIL };
+struct pkt_reconstruct {
+  enum pkt_reconstruct_res r;
+  int diff_0;
+  int diff_1;
+};
+
+void reconstruct_action(struct cap_file cf[], struct pkt_reconstruct* pr) {
+  struct buffer_packet bpread[2];
+  pr->r = PREC_FAIL;
+  for (int m1 = 0; m1 < MAX_PKTS_TO_CHECK_FOR_DROP; m1++) {
+    for (int m2 = 0; m2 <= m1; m2++) {
+      cap_npeek_bp(&cf[0], m1, &bpread[0]);
+      cap_npeek_bp(&cf[1], m2, &bpread[1]);
+      if(are_packets_equal(bpread)) {
+        pr->r = m1 == 0 && m2 == 0 ? PREC_SAME : PREC_DROP;
+        pr->diff_0 = m1;
+        pr->diff_1 = m2;
+        while (m1-- >= 0) cap_next_bp (&cf[0], &bpread[0]);
+        while (m2-- >= 0) cap_next_bp (&cf[1], &bpread[1]);
+        return;
+      }
+
+      cap_npeek_bp(&cf[0], m2, &bpread[0]);
+      cap_npeek_bp(&cf[1], m1, &bpread[1]);
+      if(are_packets_equal(bpread)) {
+        pr->r = PREC_DROP;
+        pr->diff_0 = m2;
+        pr->diff_1 = m1;
+        while (m2-- >= 0) cap_next_bp (&cf[0], &bpread[0]);
+        while (m1-- >= 0) cap_next_bp (&cf[1], &bpread[1]);
+        return;
+      }
+    }
+  }
+};
+
 int main(int argc, char** argv) {
   setvbuf(stdout, NULL, _IONBF, 0);
   printf("~ capdiff ~\n");
 
   if (argc != 3) {
-    fprintf(stderr, "Usage %s FILE1 FILE2\n", argv[0]);
+    fprintf(stderr, "Usage %s FILE.IN FILE.OUT\n", argv[0]);
     exit(EXIT_FAILURE);
   }
   uint8_t verbose = 0;
@@ -29,52 +80,32 @@ int main(int argc, char** argv) {
            cf[0].sz/sizeof(struct buffer_packet));
   }
 
-  size_t to_read = cf[0].sz < cf[1].sz ? cf[0].sz : cf[1].sz;
+  struct pkt_reconstruct pr;
-  size_t to_read_obj = to_read / sizeof(struct buffer_packet);
-  uint16_t expected_id = 0;
   struct buffer_packet bpread[2];
-  for (size_t c = 0; c < to_read_obj; c++) {
+  int c0 = 0, c1 = 0, stop = 0;
-    for (int i = 0; i < 2; i++) cap_next_bp(&cf[i], &bpread[i]);
+  while (c0 < cf[0].sz_obj && c1 < cf[1].sz_obj && !stop) {
-    /*if (expected_id != bpread[0].ip.ap.fmt.content.clear.id || expected_id != bpread[1].ip.ap.fmt.content.clear.id) {
+    reconstruct_action(cf, &pr);
-      printf("[!!] expected id is %d, %s has id %d, %s has id %d\n",
+    c0 += pr.diff_0 + 1;
-             expected_id,
+    c1 += pr.diff_1 + 1;
-             argv[1],
+    switch (pr.r) {
-             bpread[0].ip.ap.fmt.content.clear.id,
+    case PREC_SAME:
-             argv[2],
+      // Nothing
-             bpread[1].ip.ap.fmt.content.clear.id);
+      break;
-    }*/
+    case PREC_DROP:
-
+      fprintf(stderr, "[!!] packets (%d,%d) ", c0, c1);
-    size_t s1 = bpread[0].ip.ap.fmt.headers.size, s2 = bpread[1].ip.ap.fmt.headers.size;
+      if (c0 > 0) fprintf(stderr, "%s dropped %d pkts ", cf[0].filename, pr.diff_0);
-    uint8_t is_same_size = s1 == s2;
+      if (c1 > 0) fprintf(stderr, "%s has dropped %d pkts ", cf[1].filename, pr.diff_1);
-    if (!is_same_size) {
+      fprintf(stderr, "\n");
-      printf("[!!] %s packet has size %d, %s packet has size %d for expected id %d\n",
+      break;
-             argv[1],
+    case PREC_FAIL:
-             bpread[0].ip.ap.fmt.headers.size,
+      fprintf(stderr, "[!!] Unable to remap packets (%d, %d). We should stop\n", c0, c1);
-             argv[2],
+      stop = 1;
-             bpread[1].ip.ap.fmt.headers.size,
+      break;
-             expected_id);
-    } else if (verbose) {
-      printf("[OK] %s and %s packets for expected id %d have size %d\n",
-             argv[1],
-             argv[2],
-             expected_id,
-             bpread[0].ip.ap.fmt.headers.size);
     }
-
-
-    size_t max_size = s1 > s2 ? s1 : s2;
-    for (size_t idx = sizeof(bpread[0].ip.ap.fmt.headers) + sizeof(bpread[0].ip.ap.fmt.content.clear) - sizeof(char); idx < max_size; idx++) {
-      char e1 = (&bpread[0].ip.ap.raw)[idx], e2 = (&bpread[1].ip.ap.raw)[idx];
-      if (e1 != e2) {
-        printf("[!!] for expected id %d, byte 0x%04x is different: 0x%02x vs 0x%02x\n", expected_id, (uint16_t)idx, (uint8_t)e1, (uint8_t)e2);
-      }
-    }
-
-    expected_id++;
   }
 
-  for (int i = 0; i < 2; i++) cap_unload (&cf[i]);
+  printf("parsed (%d,%d) packets\n", c0, c1);
 
-  printf("parsed %d packets\n", expected_id);
+  for (int i = 0; i < 2; i++) cap_unload (&cf[i]);
   return 0;
 }