add p4split utility

Makefile

@@ -1,10 +1,11 @@
 CFLAGS = -Wall -Werror
-TARGETS = pmerge puniq
+TARGETS = pmerge puniq p4split
 
 all: $(TARGETS)
 
 pmerge: pmerge.o pcap.o
 puniq: puniq.o pcap.o
+p4split: p4split.c pcap.o
 
 clean:
-	rm -f $(TARGETS)
+	rm -f $(TARGETS) *.o

p4split.c

@@ -0,0 +1,134 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <strings.h>
+#include "pcap.h"
+
+/* Gaah so much crap */
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <netinet/ether.h>
+#include <netinet/ip.h>
+#include <netinet/in.h>
+
+
+int
+usage(int ret)
+{
+  fprintf(stderr, "Usage: pip4split CIDR\n");
+  fprintf(stderr, "\n");
+  fprintf(stderr, "Splits pcap on stdin into up to 256 files, based on CIDR.\n");
+  return ret;
+}
+
+
+int
+parse_cidr(char *s, uint32_t *addr, uint8_t *bits)
+{
+  char           *slash = index(s, '/');
+  struct in_addr  inp;
+
+  if (slash) {
+    *slash = 0;
+    *bits = atoi(slash + 1);
+  } else {
+    *bits = 0;
+  }
+
+  if (0 == inet_aton(s, &inp)) return -1;
+  *addr = ntohl(inp.s_addr);
+
+  return 0;
+}
+  
+
+int
+main(int argc, char *argv[])
+{
+  struct pcap_file p;
+  struct pcap_file out[256];
+  int              ok = 0;
+  uint32_t         addr;
+  uint32_t         mask;
+  uint8_t          bits;
+  uint8_t          shr;
+  int              i;
+
+  if (argc != 2) return usage(0);
+  if (-1 == parse_cidr(argv[1], &addr, &bits)) return usage(0);
+  if (bits > 24) return usage(0);
+  if (bits % 8) {
+    fprintf(stderr, "Warning: routing prefix is not a multiple of 8.\n");
+  }
+
+  mask = ~((1 << (32 - bits)) - 1);
+  addr &= mask;
+  shr = bits - 8;
+
+  for (i = 0; i < 256; i += 1) {
+    out[i].f = NULL;
+  }
+
+  if (-1 == pcap_open_in(&p, stdin)) return usage(0);
+
+  while (1) {
+    struct pcap_pkthdr hdr;
+    uint8_t            octet;
+    char               frame[MAXFRAME];
+
+    ok = 1;
+    if (-1 == pcap_read_pkthdr(&p, &hdr)) break;
+    if (1 != fread(frame, hdr.caplen, 1, p.f)) break;
+
+
+    {
+      struct ether_header *eh = (struct ether_header *)frame;
+      struct iphdr        *ih = (struct iphdr *)(frame + sizeof(struct ether_header));
+      uint32_t             a;
+
+      /* VLAN tag */
+      if (ntohs(eh->ether_type) == 0x8100) {
+        ih = (struct iphdr *)((char *)ih + 4);
+      }
+
+      a = ntohl(ih->saddr);
+      if ((a & mask) != addr) {
+        a = ntohl(ih->daddr);
+        if ((a & mask) != addr) {
+          fprintf(stderr, "Warning: dropping unmatched packet %08x -> %08x\n",
+                  ntohl(ih->saddr), ntohl(ih->daddr));
+          continue;
+        }
+      }
+      octet = (a & ~mask) >> shr;
+    }
+
+    ok = 0;
+    if (! out[octet].f) {
+      char fn[9];
+      FILE *f;
+
+      sfprintf(stderr, fn, "%03d.pcap", octet);
+
+      if (NULL == (f = fopen(fn, "wb"))) break;
+      if (-1 == pcap_open_out(&out[octet], f)) break;
+    }
+
+    if (-1 == pcap_write_pkthdr(&out[octet], &hdr)) break;
+    if (1 != fwrite(frame, hdr.caplen, 1, out[octet].f)) break;
+  }
+
+  if (! ok) {
+    perror("Error");
+    return 1;
+  }
+
+  for (i = 0; i < 256; i += 1) {
+    if (out[i].f) {
+      pcap_close(&p);
+    }
+  }
+
+  return 0;
+}

pcap.c

@@ -54,6 +54,8 @@ pcap_read_pkthdr(struct pcap_file *ctx, struct pcap_pkthdr *hdr)
     hdr->len        = bswap32(hdr->len);
   }
 
+  if (hdr->caplen > MAXFRAME) return -1;
+
   return 0;
 }
 

pmerge.c

@@ -12,9 +12,9 @@ struct input_file {
 int
 usage(int ret)
 {
-  printf("Usage: pmerge FILE ...\n");
-  printf("\n");
-  printf("Merges pcap files, outputting time-ordered pcap stream\n");
+  fprintf(stderr, "Usage: pmerge FILE ...\n");
+  fprintf(stderr, "\n");
+  fprintf(stderr, "Merges pcap files, outputting time-ordered pcap stream\n");
   return ret;
 }
 
@@ -93,7 +93,7 @@ main(int argc, char *argv[])
 
     /* Make sure it'll fit */
     if (cur->next.caplen > sizeof(frame)) {
-      fprintf(stderr, "error: huge frame (size %u)\n", len);
+      fprintf(stderr, "error: huge frame (size %u)\n", (unsigned int)len);
       return EX_SOFTWARE;
     }