mirror of https://github.com/dirtbags/fluffy.git
135 lines
2.7 KiB
C
135 lines
2.7 KiB
C
#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <sysexits.h>
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#include <strings.h>
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#include "pcap.h"
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/* Gaah so much crap */
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#include <sys/socket.h>
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#include <arpa/inet.h>
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#include <netinet/ether.h>
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#include <netinet/ip.h>
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#include <netinet/in.h>
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int
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usage(int ret)
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{
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fprintf(stderr, "Usage: p4split CIDR\n");
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fprintf(stderr, "\n");
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fprintf(stderr, "Splits pcap on stdin into up to 256 files, based on CIDR.\n");
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return ret;
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}
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int
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parse_cidr(char *s, uint32_t *addr, uint8_t *bits)
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{
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char *slash = index(s, '/');
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struct in_addr inp;
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if (slash) {
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*slash = 0;
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*bits = atoi(slash + 1);
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} else {
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*bits = 0;
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}
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if (0 == inet_aton(s, &inp)) return -1;
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*addr = ntohl(inp.s_addr);
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return 0;
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}
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int
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main(int argc, char *argv[])
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{
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struct pcap_file p;
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struct pcap_file out[256];
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int ok = 0;
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uint32_t addr;
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uint32_t mask;
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uint8_t bits;
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uint8_t shr;
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int i;
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if (argc != 2) return usage(0);
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if (-1 == parse_cidr(argv[1], &addr, &bits)) return usage(0);
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if (bits > 24) return usage(0);
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if (bits % 8) {
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fprintf(stderr, "Warning: routing prefix is not a multiple of 8.\n");
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}
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mask = ~((1 << (32-bits)) - 1);
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addr &= mask;
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shr = (32-bits) - 8;
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for (i = 0; i < 256; i += 1) {
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out[i].f = NULL;
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}
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if (-1 == pcap_open_in(&p, stdin)) return usage(0);
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while (1) {
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struct pcap_pkthdr hdr;
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uint8_t octet;
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char frame[MAXFRAME];
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ok = 1;
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if (-1 == pcap_read_pkthdr(&p, &hdr)) break;
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if (1 != fread(frame, hdr.caplen, 1, p.f)) break;
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{
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struct ether_header *eh = (struct ether_header *)frame;
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struct iphdr *ih = (struct iphdr *)(frame + sizeof(struct ether_header));
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uint32_t a;
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/* VLAN tag */
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if (ntohs(eh->ether_type) == 0x8100) {
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ih = (struct iphdr *)((char *)ih + 4);
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}
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a = ntohl(ih->saddr);
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if ((a & mask) != addr) {
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a = ntohl(ih->daddr);
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if ((a & mask) != addr) {
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fprintf(stderr, "Warning: dropping unmatched packet %08x -> %08x\n",
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ntohl(ih->saddr), ntohl(ih->daddr));
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continue;
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}
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}
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octet = (a & ~mask) >> shr;
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}
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ok = 0;
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if (! out[octet].f) {
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char fn[9];
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FILE *f;
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sprintf(fn, "%d.pcap", octet);
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if (NULL == (f = fopen(fn, "wb"))) break;
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if (-1 == pcap_open_out(&out[octet], f)) break;
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}
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if (-1 == pcap_write_pkthdr(&out[octet], &hdr)) break;
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if (1 != fwrite(frame, hdr.caplen, 1, out[octet].f)) break;
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}
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if (! ok) {
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perror("Error");
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return 1;
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}
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for (i = 0; i < 256; i += 1) {
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if (out[i].f) {
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pcap_close(&p);
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}
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}
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return 0;
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}
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