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#include <stdio.h>
#include <pcap.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <string.h>
#include <dlfcn.h>
#include "ct.h"
#include "proto.h"
#include "../../../include/helper.h"
#include "test.h"
#include <libnetfilter_queue/pktbuff.h>
struct cthelper_test_stats cthelper_test_stats;
enum {
TEST_NORMAL = 0,
TEST_DNAT,
};
static int
cthelper_process_packet(const uint8_t *pkt, uint32_t pktlen,
struct ctd_helper *h, int proto, uint16_t port,
int type)
{
struct pkt_buff *pktb;
struct cthelper_proto_l2l3_helper *l3h;
struct cthelper_proto_l4_helper *l4h;
unsigned int l3hdr_len, l4protonum;
struct nf_ct_entry *ct;
int ret, this_proto;
uint32_t dataoff, ctinfo = 0;
l3h = cthelper_proto_l2l3_helper_find(pkt, &l4protonum, &l3hdr_len);
if (l3h == NULL) {
fprintf(stderr, "Unsupported layer 3 protocol, skipping.\n");
return -1;
}
l4h = cthelper_proto_l4_helper_find(pkt, l4protonum);
if (l4h == NULL) {
fprintf(stderr, "Unsupported layer 4 protocol, skipping.\n");
return -1;
}
/* get layer 3 header. */
pkt += l3h->l2hdr_len;
pktlen -= l3h->l2hdr_len;
/* skip packet with mismatching protocol */
this_proto = l3h->l4pkt_proto(pkt);
if (this_proto != proto) {
cthelper_test_stats.pkt_mismatch_proto++;
return 0;
}
/* Look for the fake conntrack. */
ct = ct_find(pkt, l3hdr_len, l3h, l4h, &ctinfo);
if (ct == NULL) {
/* It doesn't exist any, create one. */
ct = ct_alloc(pkt, l3hdr_len, l3h, l4h);
if (ct == NULL) {
fprintf(stderr, "Not enough memory\n");
return -1;
}
ct_add(ct);
ctinfo += IP_CT_NEW;
} else
ctinfo += IP_CT_ESTABLISHED;
/* skip packets with mismatching ports */
if (!l4h->l4ct_cmp_port(ct->myct->ct, ntohs(port))) {
cthelper_test_stats.pkt_mismatch_port++;
return -1;
}
/*
* FIXME: reminder, implement this below in the kernel for cthelper.
*/
/* This packet contains no data, skip it. */
/* if (l4h->l4pkt_no_data && l4h->l4pkt_no_data(pkt + l3hdr_len)) {
NFG_DEBUG("skipping packet with no data\n");
continue;
} */
/* Create the fake network buffer. */
pktb = pktb_alloc(AF_INET, pkt, pktlen, 128);
if (pktb == NULL) {
fprintf(stderr, "Not enough memory\n");
return -1;
}
dataoff = l3h->l3pkt_hdr_len(pkt);
if (dataoff > pktb_len(pktb)) {
fprintf(stderr, "wrong layer 3 offset: %d > %d\n",
dataoff, pktb_len(pktb));
return -1;
}
/* tweak to run DNAT mangling code using the same PCAP file. */
if (type == TEST_DNAT) {
struct nf_conntrack *tmp = ct->myct->ct;
/* as long as this is tested, who cares the destination IP? */
in_addr_t addr = inet_addr("1.1.1.1");
/* clone the real conntrack, to add DNAT information */
ct->myct->ct = nfct_clone(ct->myct->ct);
/* set fake DNAT information */
nfct_set_attr_u32(ct->myct->ct, ATTR_STATUS, IPS_DST_NAT);
nfct_set_attr_u32(ct->myct->ct, ATTR_ORIG_IPV4_DST, addr);
/* pass it to helper */
ret = h->cb(pktb, dataoff, ct->myct, ctinfo);
/* restore real conntrack */
nfct_destroy(ct->myct->ct);
ct->myct->ct = tmp;
if (pktb_mangled(pktb)) {
uint32_t i;
uint8_t *data = pktb_network_header(pktb);
printf("\e[1;31mmangled content: ");
for (i=0; i < pktb_len(pktb); i++)
printf("%c", data[i]);
printf("\e[0m\n");
}
} else
ret = h->cb(pktb, dataoff, ct->myct, ctinfo);
pktb_free(pktb);
return ret;
}
static int
cthelper_test(const char *pcapfile, const char *helper_name,
int l4proto, uint16_t port, int type)
{
struct pcap_pkthdr pcaph;
char errbuf[PCAP_ERRBUF_SIZE];
const u_char *pkt;
pcap_t *handle;
struct ctd_helper *h;
h = helper_find("/usr/lib/conntrack-tools",
helper_name, l4proto, RTLD_NOW);
if (h == NULL) {
fprintf(stderr, "couldn't find helper: %s\n", helper_name);
return -1;
}
handle = pcap_open_offline(pcapfile, errbuf);
if (handle == NULL) {
fprintf(stderr, "couldn't open pcap file %s: %s\n",
pcapfile, errbuf);
return -1;
}
while ((pkt = pcap_next(handle, &pcaph)) != NULL) {
cthelper_test_stats.pkts++;
cthelper_process_packet(pkt, pcaph.caplen, h, l4proto, port,
type);
}
ct_flush();
pcap_close(handle);
return 0;
}
int main(int argc, char *argv[])
{
int ret, l4proto, type = TEST_NORMAL;
if (argc < 5 || argc > 6) {
fprintf(stderr, "Wrong usage:\n");
fprintf(stderr, "%s <pcap_file> <helper-name> <proto> "
"<port> [dnat]\n",
argv[0]);
fprintf(stderr, "example: %s file.pcap ftp tcp 21\n", argv[0]);
exit(EXIT_FAILURE);
}
if (strncmp("tcp", argv[3], strlen("tcp")) == 0)
l4proto = IPPROTO_TCP;
else if (strncmp("udp", argv[3], strlen("udp")) == 0)
l4proto = IPPROTO_UDP;
else {
fprintf(stderr, "%s not supported, send a patch to Pablo\n",
argv[3]);
exit(EXIT_FAILURE);
}
if (argc == 6) {
if (strncmp("dnat", argv[5], strlen("dnat")) == 0) {
type = TEST_DNAT;
printf("test dnat\n");
}
}
/* Initialization of supported layer 3 and 4 protocols here. */
l2l3_ipv4_init();
l4_tcp_init();
l4_udp_init();
if (cthelper_test(argv[1], argv[2], l4proto, atoi(argv[4]), type) < 0)
ret = EXIT_FAILURE;
else
ret = EXIT_SUCCESS;
printf("\e[1;34mTest results: expect_created=%d packets=%d "
"packets_skipped=%d\e[0m\n",
cthelper_test_stats.ct_expect_created,
cthelper_test_stats.pkts,
cthelper_test_stats.pkt_mismatch_proto +
cthelper_test_stats.pkt_mismatch_port);
return ret;
}
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