// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <arpa/inet.h>
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <limits.h>
#include <linux/filter.h>
#include <linux/bpf.h>
#include <linux/if_packet.h>
#include <linux/if_vlan.h>
#include <linux/virtio_net.h>
#include <net/if.h>
#include <net/ethernet.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <poll.h>
#include <sched.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "psock_lib.h"
static bool cfg_use_bind;
static bool cfg_use_csum_off;
static bool cfg_use_csum_off_bad;
static bool cfg_use_dgram;
static bool cfg_use_gso;
static bool cfg_use_qdisc_bypass;
static bool cfg_use_vlan;
static bool cfg_use_vnet;
static char *cfg_ifname = "lo";
static int cfg_mtu = 1500;
static int cfg_payload_len = DATA_LEN;
static int cfg_truncate_len = INT_MAX;
static uint16_t cfg_port = 8000;
/* test sending up to max mtu + 1 */
#define TEST_SZ (sizeof(struct virtio_net_hdr) + ETH_HLEN + ETH_MAX_MTU + 1)
static char tbuf[TEST_SZ], rbuf[TEST_SZ];
static unsigned long add_csum_hword(const uint16_t *start, int num_u16)
{
unsigned long sum = 0;
int i;
for (i = 0; i < num_u16; i++)
sum += start[i];
return sum;
}
static uint16_t build_ip_csum(const uint16_t *start, int num_u16,
unsigned long sum)
{
sum += add_csum_hword(start, num_u16);
while (sum >> 16)
sum = (sum & 0xffff) + (sum >> 16);
return ~sum;
}
static int build_vnet_header(void *header)
{
struct virtio_net_hdr *vh = header;
vh->hdr_len = ETH_HLEN + sizeof(struct iphdr) + sizeof(struct udphdr);
if (cfg_use_csum_off) {
vh->flags |= VIRTIO_NET_HDR_F_NEEDS_CSUM;
vh->csum_start = ETH_HLEN + sizeof(struct iphdr);
vh->csum_offset = __builtin_offsetof(struct udphdr, check);
/* position check field exactly one byte beyond end of packet */
if (cfg_use_csum_off_bad)
vh->csum_start += sizeof(struct udphdr) + cfg_payload_len -
vh->csum_offset - 1;
}
if (cfg_use_gso) {
vh->gso_type = VIRTIO_NET_HDR_GSO_UDP;
vh->gso_size = cfg_mtu - sizeof(struct iphdr);
}
return sizeof(*vh);
}
static int build_eth_header(void *header)
{
struct ethhdr *eth = header;
if (cfg_use_vlan) {
uint16_t *tag = header + ETH_HLEN;
eth->h_proto = htons(ETH_P_8021Q);
tag[1] = htons(ETH_P_IP);
return ETH_HLEN + 4;
}
eth->h_proto = htons(ETH_P_IP);
return ETH_HLEN;
}
static int build_ipv4_header(void *header, int payload_len)
{
struct iphdr *iph = header;
iph->ihl = 5;
iph->version = 4;
iph->ttl = 8;
iph->tot_len = htons(sizeof(*iph) + sizeof(struct udphdr) + payload_len);
iph->id = htons(1337);
iph->protocol = IPPROTO_UDP;
iph->saddr = htonl((172 << 24) | (17 << 16) | 2);
iph->daddr = htonl((172 << 24) | (17 << 16) | 1);
iph->check = build_ip_csum((void *) iph, iph->ihl << 1, 0);
return iph->ihl << 2;
}
static int build_udp_header(void *header, int payload_len)
{
const int alen = sizeof(uint32_t);
struct udphdr *udph = header;
int len = sizeof(*udph) + payload_len;
udph->source = htons(9);
udph->dest = htons(cfg_port);
udph->len = htons(len);
if (cfg_use_csum_off)
udph->check = build_ip_csum(header - (2 * alen), alen,
htons(IPPROTO_UDP) + udph->len);
else
udph->check = 0;
return sizeof(*udph);
}
static int build_packet(int payload_len)
{
int off = 0;
off += build_vnet_header(tbuf);
off += build_eth_header(tbuf + off);
off += build_ipv4_header(tbuf + off, payload_len);
off += build_udp_header(tbuf + off, payload_len);
if (off + payload_len > sizeof(tbuf))
error(1, 0, "payload length exceeds max");
memset(tbuf + off, DATA_CHAR, payload_len);
return off + payload_len;
}
static void do_bind(int fd)
{
struct sockaddr_ll laddr = {0};
laddr.sll_family = AF_PACKET;
laddr.sll_protocol = htons(ETH_P_IP);
laddr.sll_ifindex = if_nametoindex(cfg_ifname);
if (!laddr.sll_ifindex)
error(1, errno, "if_nametoindex");
if (bind(fd, (void *)&laddr, sizeof(laddr)))
error(1, errno, "bind");
}
static void do_send(int fd, char *buf, int len)
{
int ret;
if (!cfg_use_vnet) {
buf += sizeof(struct virtio_net_hdr);
len -= sizeof(struct virtio_net_hdr);
}
if (cfg_use_dgram) {
buf += ETH_HLEN;
len -= ETH_HLEN;
}
if (cfg_use_bind) {
ret = write(fd, buf, len);
} else {
struct sockaddr_ll laddr = {0};
laddr.sll_protocol = htons(ETH_P_IP);
laddr.sll_ifindex = if_nametoindex(cfg_ifname);
if (!laddr.sll_ifindex)
error(1, errno, "if_nametoindex");
ret = sendto(fd, buf, len, 0, (void *)&laddr, sizeof(laddr));
}
if (ret == -1)
error(1, errno, "write");
if (ret != len)
error(1, 0, "write: %u %u", ret, len);
fprintf(stderr, "tx: %u\n", ret);
}
static int do_tx(void)
{
const int one = 1;
int fd, len;
fd = socket(PF_PACKET, cfg_use_dgram ? SOCK_DGRAM : SOCK_RAW, 0);
if (fd == -1)
error(1, errno, "socket t");
if (cfg_use_bind)
do_bind(fd);
if (cfg_use_qdisc_bypass &&
setsockopt(fd, SOL_PACKET, PACKET_QDISC_BYPASS, &one, sizeof(one)))
error(1, errno, "setsockopt qdisc bypass");
if (cfg_use_vnet &&
setsockopt(fd, SOL_PACKET, PACKET_VNET_HDR, &one, sizeof(one)))
error(1, errno, "setsockopt vnet");
len = build_packet(cfg_payload_len);
if (cfg_truncate_len < len)
len = cfg_truncate_len;
do_send(fd, tbuf, len);
if (close(fd))
error(1, errno, "close t");
return len;
}
static int setup_rx(void)
{
struct timeval tv = { .tv_usec = 100 * 1000 };
struct sockaddr_in raddr = {0};
int fd;
fd = socket(PF_INET, SOCK_DGRAM, 0);
if (fd == -1)
error(1, errno, "socket r");
if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
error(1, errno, "setsockopt rcv timeout");
raddr.sin_family = AF_INET;
raddr.sin_port = htons(cfg_port);
raddr.sin_addr.s_addr = htonl(INADDR_ANY);
if (bind(fd, (void *)&raddr, sizeof(raddr)))
error(1, errno, "bind r");
return fd;
}
static void do_rx(int fd, int expected_len, char *expected)
{
int ret;
ret = recv(fd, rbuf, sizeof(rbuf), 0);
if (ret == -1)
error(1, errno, "recv");
if (ret != expected_len)
error(1, 0, "recv: %u != %u", ret, expected_len);
if (memcmp(rbuf, expected, ret))
error(1, 0, "recv: data mismatch");
fprintf(stderr, "rx: %u\n", ret);
}
static int setup_sniffer(void)
{
struct timeval tv = { .tv_usec = 100 * 1000 };
int fd;
fd = socket(PF_PACKET, SOCK_RAW, 0);
if (fd == -1)
error(1, errno, "socket p");
if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
error(1, errno, "setsockopt rcv timeout");
pair_udp_setfilter(fd);
do_bind(fd);
return fd;
}
static void parse_opts(int argc, char **argv)
{
int c;
while ((c = getopt(argc, argv, "bcCdgl:qt:vV")) != -1) {
switch (c) {
case 'b':
cfg_use_bind = true;
break;
case 'c':
cfg_use_csum_off = true;
break;
case 'C':
cfg_use_csum_off_bad = true;
break;
case 'd':
cfg_use_dgram = true;
break;
case 'g':
cfg_use_gso = true;
break;
case 'l':
cfg_payload_len = strtoul(optarg, NULL, 0);
break;
case 'q':
cfg_use_qdisc_bypass = true;
break;
case 't':
cfg_truncate_len = strtoul(optarg, NULL, 0);
break;
case 'v':
cfg_use_vnet = true;
break;
case 'V':
cfg_use_vlan = true;
break;
default:
error(1, 0, "%s: parse error", argv[0]);
}
}
if (cfg_use_vlan && cfg_use_dgram)
error(1, 0, "option vlan (-V) conflicts with dgram (-d)");
if (cfg_use_csum_off && !cfg_use_vnet)
error(1, 0, "option csum offload (-c) requires vnet (-v)");
if (cfg_use_csum_off_bad && !cfg_use_csum_off)
error(1, 0, "option csum bad (-C) requires csum offload (-c)");
if (cfg_use_gso && !cfg_use_csum_off)
error(1, 0, "option gso (-g) requires csum offload (-c)");
}
static void run_test(void)
{
int fdr, fds, total_len;
fdr = setup_rx();
fds = setup_sniffer();
total_len = do_tx();
/* BPF filter accepts only this length, vlan changes MAC */
if (cfg_payload_len == DATA_LEN && !cfg_use_vlan)
do_rx(fds, total_len - sizeof(struct virtio_net_hdr),
tbuf + sizeof(struct virtio_net_hdr));
do_rx(fdr, cfg_payload_len, tbuf + total_len - cfg_payload_len);
if (close(fds))
error(1, errno, "close s");
if (close(fdr))
error(1, errno, "close r");
}
int main(int argc, char **argv)
{
parse_opts(argc, argv);
if (system("ip link set dev lo mtu 1500"))
error(1, errno, "ip link set mtu");
if (system("ip addr add dev lo 172.17.0.1/24"))
error(1, errno, "ip addr add");
if (system("sysctl -w net.ipv4.conf.lo.accept_local=1"))
error(1, errno, "sysctl lo.accept_local");
run_test();
fprintf(stderr, "OK\n\n");
return 0;
}
Codebase Browser
linux