demo/linux/pcap/udp.c
2025-03-08 21:58:23 +08:00

353 lines
8.6 KiB
C

#include <pcap.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define STR_MAC_SRC "1C:75:08:6A:4E:6E"
#define STR_MAC_DST "1C:1B:0D:2E:A9:99"
#define STR_IP_SRC "192.168.2.32"
#define STR_IP_DST "192.168.2.24"
#define STR_PORT_SRC "40103"
#define STR_PORT_DST "40103"
#define UDP_CHECKSUM_ENABLE 1
struct udp_cfg_s {
char *mac_src;
char *mac_dst;
char *ip_src;
char *ip_dst;
char *port_src;
char *port_dst;
};
struct udp_cfg_s udp_cfg = {
.mac_src = STR_MAC_SRC,
.mac_dst = STR_MAC_DST,
.ip_src = STR_IP_SRC,
.ip_dst = STR_IP_DST,
.port_src = STR_PORT_SRC,
.port_dst = STR_PORT_DST,
};
struct udp_s {
/* MAC */
uint8_t mac_dst[6];
uint8_t mac_src[6];
uint8_t ip_type[2]; // 08 00 for IPv4 type
/* IP */
uint8_t ver_head_length; // 0x45 for IPv4 and head length is 5*4=20 bytes
uint8_t tos; // type of service, normal 0
uint8_t ip_total_length[2]; // 28 + user data length, e.g. 00 20 for 32 bytes
uint8_t id[2];
uint8_t offset[2];
uint8_t ttl; // time to live, normal 0x80
uint8_t prototal; // 0x11 for UDP prototal
uint8_t ip_checksum[2]; // normal 00 00
uint8_t ip_src[4]; // e.g. C0 A8 02 18 is for 192.168.2.24
uint8_t ip_dst[4]; // e.g. C0 A8 02 20 is for 192.168.2.32
/* UDP */
uint8_t port_src[2]; // e.g. 26 E5 is for 9957
uint8_t port_dst[2]; // e.g. 0E D3 is for 3795
uint8_t udp_total_length[2]; // 8 + user data length, e.g. 00 0C for 12 bytes
uint8_t udp_checksum[2];
/* data */
uint8_t data[64];
};
static int char2idx(char c, uint8_t *idx)
{
if (c >= '0' && c <= '9') {
*idx = c - '0';
} else if (c >= 'A' && c <= 'F') {
*idx = c - 'A' + 10;
} else if (c >= 'a' && c <= 'f') {
*idx = c - 'a' + 10;
} else {
return -1;
}
return 0;
}
static int str2mac(char *str, uint8_t *mac)
{
int i, ret;
uint8_t high, low;
for (i = 0; i < 6; i++) {
if (i >= 5) {
if (str[2] != '\0') {
return -2;
}
} else {
if (str[2] != '-' && str[2] != ':' && str[2] != ' ' && str[2] != '_') {
return -3;
}
}
ret = char2idx(str[0], &high);
ret |= char2idx(str[1], &low);
if (ret) {
return -1;
}
mac[i] = (high << 4) | low;
str += 3;
}
return 0;
}
static int str2ip(char *str, uint8_t *ip)
{
char c;
int idx, len;
uint8_t num;
idx = 0;
len = 0;
num = 0;
while (1) {
c = *str;
if (c >= '0' && c <= '9') {
c = c - '0';
num = num * 10 + c;
len++;
if (len > 3) {
return -3;
}
} else if (c == '.') {
ip[idx++] = num;
num = 0;
len = 0;
if (idx >= 4) {
break;
}
} else if (c == '\0') {
ip[idx++] = num;
break;
} else {
return -1;
}
str++;
}
if (idx == 4) {
return 0;
} else {
return -2;
}
}
static int str2port(char *str, uint8_t *port)
{
char c;
int idx, len;
uint16_t num;
len = 0;
num = 0;
while (1) {
c = *str;
if (c >= '0' && c <= '9') {
c = c - '0';
num = num * 10 + c;
len++;
if (len > 5) {
return -2;
}
} else if (c == '\0') {
break;
} else {
return -1;
}
str++;
}
port[0] = (num >> 8) & 0xFF;
port[1] = num & 0xFF;
return 0;
}
void padding_length(struct udp_s *udp, uint16_t length)
{
uint16_t num;
num = length + 28;
udp->ip_total_length[0] = (num >> 8) & 0xFF;
udp->ip_total_length[1] = num & 0xFF;
num = length + 8;
udp->udp_total_length[0] = (num >> 8) & 0xFF;
udp->udp_total_length[1] = num & 0xFF;
}
static uint16_t checksum(uint32_t init, uint16_t *addr, uint16_t len)
{
uint32_t sum = init;
while (len > 1) {
sum += *addr++;
len -= 2;
}
if (len == 1) {
sum += *(uint8_t *)addr;
}
while (sum >> 16) {
sum = (sum >> 16) + (sum & 0xFFFF);
sum += (sum >> 16);
}
return (uint16_t)~sum;
}
void checksum_ip(struct udp_s *packet)
{
uint32_t sum;
uint16_t *p;
packet->ip_checksum[0] = 0;
packet->ip_checksum[1] = 0;
p = (uint16_t *)(&(packet->ver_head_length));
sum = checksum(0, p, 20);
packet->ip_checksum[0] = sum & 0xFF;
packet->ip_checksum[1] = (sum >> 8) & 0xFF;
}
void checksum_udp(struct udp_s *packet)
{
#if UDP_CHECKSUM_ENABLE
uint32_t sum = 0;
uint16_t *p;
uint16_t length;
/* pseudo_header */
p = (uint16_t *)(&(packet->ip_src));
sum = sum + p[0] + p[1];
p = (uint16_t *)(&(packet->ip_dst));
sum = sum + p[0] + p[1];
sum = sum + (packet->prototal << 8);
p = (uint16_t *)(&(packet->udp_total_length));
sum = sum + p[0];
/* UDP head and data */
packet->udp_checksum[0] = 0;
packet->udp_checksum[1] = 0;
p = (uint16_t *)(&(packet->port_src));
length = (packet->udp_total_length[0] << 8) + packet->udp_total_length[1];
sum = checksum(sum, p, length);
packet->udp_checksum[0] = sum & 0xFF;
packet->udp_checksum[1] = (sum >> 8) & 0xFF;
#else
packet->udp_checksum[0] = 0;
packet->udp_checksum[1] = 0;
#endif
}
int udp_create_default(struct udp_cfg_s *cfg, struct udp_s *udp)
{
int ret;
/* MAC */
ret = str2mac(cfg->mac_dst, udp->mac_dst);
if (ret) {
return -1;
}
ret = str2mac(cfg->mac_src, udp->mac_src);
if (ret) {
return -2;
}
udp->ip_type[0] = 0x08; // 08 00 for IPv4 type
udp->ip_type[1] = 0x00;
/* IP */
udp->ver_head_length = 0x45; // 0x45 for IPv4 and head length is 5*4=20 bytes
udp->tos = 0; // type of service, normal 0
udp->ip_total_length[0] = 0; // 28 + user data length, e.g. 00 20 for 32 bytes
udp->ip_total_length[1] = 0;
udp->id[0] = 0;
udp->id[1] = 0;
udp->offset[0] = 0;
udp->offset[1] = 0;
udp->ttl = 0x80; // time to live, normal 0x80
udp->prototal = 0x11; // 0x11 for UDP prototal
udp->ip_checksum[0] = 0;
udp->ip_checksum[1] = 0;
ret = str2ip(cfg->ip_src, udp->ip_src); // e.g. C0 A8 02 18 is for 192.168.2.24
if (ret) {
return -3;
}
ret = str2ip(cfg->ip_dst, udp->ip_dst); // e.g. C0 A8 02 20 is for 192.168.2.32
if (ret) {
return -4;
}
/* UDP */
ret = str2port(cfg->port_src, udp->port_src); // e.g. 26 E5 is for 9957
if (ret) {
return -5;
}
ret = str2port(cfg->port_dst, udp->port_dst); // e.g. 0E D3 is for 3795
if (ret) {
return -6;
}
udp->udp_total_length[0] = 0; // 8 + user data length, e.g. 00 0C for 12 bytes
udp->udp_total_length[1] = 0;
udp->udp_checksum[0] = 0;
udp->udp_checksum[1] = 0;
return 0;
}
struct udp_s udp;
void data_calc(void)
{
int ret, i, j;
float val;
ret = udp_create_default(&udp_cfg, &udp);
if (ret) {
printf("%s, err=%d\r\n", __FUNCTION__, ret);
}
for (i = 0; i < 8; i += 2) {
val = i * i;
for (j = 0; j < 4; j++) {
udp.data[i * 4 + j] = ((uint8_t *)(&val))[j];
}
udp.data[i * 4 + 4] = 0x00;
udp.data[i * 4 + 5] = 0x00;
udp.data[i * 4 + 6] = 0x80;
udp.data[i * 4 + 7] = 0x7F;
}
padding_length(&udp, 32);
checksum_ip(&udp);
checksum_udp(&udp);
}
int main() {
char errbuf[PCAP_ERRBUF_SIZE];
pcap_t *handle;
int i;
// 打开网络设备
handle = pcap_open_live("eth0", BUFSIZ, 0, 1000, errbuf);
if (handle == NULL) {
fprintf(stderr, "Couldn't open device: %s\n", errbuf);
return 1;
}
data_calc();
for (i = 0; i < 100; i++) {
int ret = pcap_inject(handle, &udp, sizeof(udp));
if (ret == -1) {
fprintf(stderr, "Couldn't send packet: %s\n", pcap_geterr(handle));
pcap_close(handle);
return 1;
} else {
printf("Packet sent successfully (%d bytes)\n", ret);
}
usleep(1000);
}
// 关闭网络设备
pcap_close(handle);
return 0;
}