/* Written from scratch, but kernel-to-user space API usage
* dissected from lolpcap:
* Copyright 2011, Chetan Loke <loke.chetan@gmail.com>
* License: GPL, version 2.0
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <poll.h>
#include <unistd.h>
#include <signal.h>
#include <inttypes.h>
#include <sys/socket.h>
#include <sys/mman.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#ifndef likely
# define likely(x) __builtin_expect(!!(x), 1)
#endif
#ifndef unlikely
# define unlikely(x) __builtin_expect(!!(x), 0)
#endif
struct block_desc {
uint32_t version;
uint32_t offset_to_priv;
struct tpacket_hdr_v1 h1;
};
struct ring {
struct iovec *rd;
uint8_t *map;
struct tpacket_req3 req;
};
static unsigned long packets_total = 0, bytes_total = 0;
static sig_atomic_t sigint = 0;
static void sighandler(int num)
{
sigint = 1;
}
static int setup_socket(struct ring *ring, char *netdev)
{
int err, i, fd, v = TPACKET_V3;
struct sockaddr_ll ll;
unsigned int blocksiz = 1 << 22, framesiz = 1 << 11;
unsigned int blocknum = 64;
fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
if (fd < 0) {
perror("socket");
exit(1);
}
err = setsockopt(fd, SOL_PACKET, PACKET_VERSION, &v, sizeof(v));
if (err < 0) {
perror("setsockopt");
exit(1);
}
memset(&ring->req, 0, sizeof(ring->req));
ring->req.tp_block_size = blocksiz;
ring->req.tp_frame_size = framesiz;
ring->req.tp_block_nr = blocknum;
ring->req.tp_frame_nr = (blocksiz * blocknum) / framesiz;
ring->req.tp_retire_blk_tov = 60;
ring->req.tp_feature_req_word = TP_FT_REQ_FILL_RXHASH;
err = setsockopt(fd, SOL_PACKET, PACKET_RX_RING, &ring->req,
sizeof(ring->req));
if (err < 0) {
perror("setsockopt");
exit(1);
}
ring->map = mmap(NULL, ring->req.tp_block_size * ring->req.tp_block_nr,
PROT_READ | PROT_WRITE, MAP_SHARED | MAP_LOCKED, fd, 0);
if (ring->map == MAP_FAILED) {
perror("mmap");
exit(1);
}
ring->rd = malloc(ring->req.tp_block_nr * sizeof(*ring->rd));
assert(ring->rd);
for (i = 0; i < ring->req.tp_block_nr; ++i) {
ring->rd[i].iov_base = ring->map + (i * ring->req.tp_block_size);
ring->rd[i].iov_len = ring->req.tp_block_size;
}
memset(&ll, 0, sizeof(ll));
ll.sll_family = PF_PACKET;
ll.sll_protocol = htons(ETH_P_ALL);
ll.sll_ifindex = if_nametoindex(netdev);
ll.sll_hatype = 0;
ll.sll_pkttype = 0;
ll.sll_halen = 0;
err = bind(fd, (struct sockaddr *) &ll, sizeof(ll));
if (err < 0) {
perror("bind");
exit(1);
}
return fd;
}
static void display(struct tpacket3_hdr *ppd)
{
struct ethhdr *eth = (struct ethhdr *) ((uint8_t *) ppd + ppd->tp_mac);
struct iphdr *ip = (struct iphdr *) ((uint8_t *) eth + ETH_HLEN);
if (eth->h_proto == htons(ETH_P_IP)) {
struct sockaddr_in ss, sd;
char sbuff[NI_MAXHOST], dbuff[NI_MAXHOST];
memset(&ss, 0, sizeof(ss));
ss.sin_family = PF_INET;
ss.sin_addr.s_addr = ip->saddr;
getnameinfo((struct sockaddr *) &ss, sizeof(ss),
sbuff, sizeof(sbuff), NULL, 0, NI_NUMERICHOST);
memset(&sd, 0, sizeof(sd));
sd.sin_family = PF_INET;
sd.sin_addr.s_addr = ip->daddr;
getnameinfo((struct sockaddr *) &sd, sizeof(sd),
dbuff, sizeof(dbuff), NULL, 0, NI_NUMERICHOST);
printf("%s -> %s, ", sbuff, dbuff);
}
printf("rxhash: 0x%x\n", ppd->hv1.tp_rxhash);
}
static void walk_block(struct block_desc *pbd, const int block_num)
{
int num_pkts = pbd->h1.num_pkts, i;
unsigned long bytes = 0;
struct tpacket3_hdr *ppd;
ppd = (struct tpacket3_hdr *) ((uint8_t *) pbd +
pbd->h1.offset_to_first_pkt);
for (i = 0; i < num_pkts; ++i) {
bytes += ppd->tp_snaplen;
display(ppd);
ppd = (struct tpacket3_hdr *) ((uint8_t *) ppd +
ppd->tp_next_offset);
}
packets_total += num_pkts;
bytes_total += bytes;
}
static void flush_block(struct block_desc *pbd)
{
pbd->h1.block_status = TP_STATUS_KERNEL;
}
static void teardown_socket(struct ring *ring, int fd)
{
munmap(ring->map, ring->req.tp_block_size * ring->req.tp_block_nr);
free(ring->rd);
close(fd);
}
int main(int argc, char **argp)
{
int fd, err;
socklen_t len;
struct ring ring;
struct pollfd pfd;
unsigned int block_num = 0, blocks = 64;
struct block_desc *pbd;
struct tpacket_stats_v3 stats;
if (argc != 2) {
fprintf(stderr, "Usage: %s INTERFACE\n", argp[0]);
return EXIT_FAILURE;
}
signal(SIGINT, sighandler);
memset(&ring, 0, sizeof(ring));
fd = setup_socket(&ring, argp[argc - 1]);
assert(fd > 0);
memset(&pfd, 0, sizeof(pfd));
pfd.fd = fd;
pfd.events = POLLIN | POLLERR;
pfd.revents = 0;
while (likely(!sigint)) {
pbd = (struct block_desc *) ring.rd[block_num].iov_base;
if ((pbd->h1.block_status & TP_STATUS_USER) == 0) {
poll(&pfd, 1, -1);
continue;
}
walk_block(pbd, block_num);
flush_block(pbd);
block_num = (block_num + 1) % blocks;
}
len = sizeof(stats);
err = getsockopt(fd, SOL_PACKET, PACKET_STATISTICS, &stats, &len);
if (err < 0) {
perror("getsockopt");
exit(1);
}
fflush(stdout);
printf("\nReceived %u packets, %lu bytes, %u dropped, freeze_q_cnt: %u\n",
stats.tp_packets, bytes_total, stats.tp_drops,
stats.tp_freeze_q_cnt);
teardown_socket(&ring, fd);
return 0;
}
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