使用raw socket构造UDP包不成功
抓不到包，请大家帮看看，先行谢过了。第一次接触raw socket编程，实在不知怎么搞了。
#include <errno.h>#include <sys/socket.h>#include <arpa/inet.h>#include <netinet/in.h>#include <netinet/ip.h>#include <netinet/udp.h>#include <sys/time.h>#include <string.h>#include <iostream>using namespace std;const int LISTEN_PORT = 7800;const int PACK_LEN = 8192;struct psdhdr{ u_int32_t saddr; u_int32_t daddr; u_int8_t zero; u_int8_t protocol; u_int16_t len;};u_int16_t checksum(u_int16_t *buffer, int size);int main(int argc, char *argv[]){ char payload[] = "hello"; struct sockaddr_in sin, din; memset(&sin, 0, sizeof(struct sockaddr_in)); memset(&din, 0, sizeof(struct sockaddr_in)); sin.sin_family = AF_INET; din.sin_family = AF_INET; sin.sin_addr.s_addr = inet_addr("19.9.0.95"); din.sin_addr.s_addr = inet_addr("18.8.6.66"); sin.sin_port = htons(LISTEN_PORT); din.sin_port = htons(LISTEN_PORT); const int listen_fd = socket(PF_INET, SOCK_RAW, IPPROTO_UDP); if (listen_fd < 0) { cout << "system error [ " << errno << ":" << strerror(errno) << "]"<< endl; return 1; } if (bind(listen_fd, (const struct sockaddr *)&sin, sizeof(sin)) < 0) { close(listen_fd); cout << "system error [ " << errno << ":" << strerror(errno) << "]"<< endl; return 1; } int on = 1; if (setsockopt(listen_fd, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on)) < 0) { cout << "system error [ " << errno << ":" << strerror(errno) << "]" << endl; return 1; } char buf[PACK_LEN] = {0}; struct iphdr *iphdr = (struct iphdr *) buf; struct psdhdr psd; struct udphdr *pudphdr = (struct udphdr *) (buf+sizeof(struct iphdr)); memcpy(buf+sizeof(struct iphdr)+sizeof(struct udphdr), payload, strlen(payload)); const int data_len = sizeof(struct iphdr)+sizeof(struct udphdr)+strlen(payload); iphdr->ihl = 5; iphdr->version = 4; iphdr->tos = 0; iphdr->tot_len = data_len; iphdr->id = htons(random()); iphdr->frag_off = 0; iphdr->ttl = 0xff; iphdr->protocol = IPPROTO_UDP; iphdr->check = 0; iphdr->saddr = sin.sin_addr.s_addr; iphdr->daddr = din.sin_addr.s_addr; iphdr->check = checksum((u_int16_t *)buf, sizeof(struct iphdr)); pudphdr->source = sin.sin_port; pudphdr->dest = din.sin_port; pudphdr->len = htons(sizeof(struct udphdr)+strlen(payload)); pudphdr->check = 0; psd.saddr = iphdr->saddr; psd.daddr = iphdr->daddr; psd.zero = 0; psd.protocol = IPPROTO_UDP; psd.len = pudphdr->len; char tmp[sizeof(struct psdhdr) + ntohs(pudphdr->len)]; struct psdhdr *ppsdhdr = (struct psdhdr *) tmp; ppsdhdr->saddr = iphdr->saddr; ppsdhdr->daddr = iphdr->daddr; ppsdhdr->zero = 0; ppsdhdr->protocol = IPPROTO_UDP; ppsdhdr->len = pudphdr->len; memcpy(tmp+sizeof(struct psdhdr), buf+sizeof(struct iphdr), ntohs(pudphdr->len)); pudphdr->check = checksum((u_int16_t *)tmp, sizeof(tmp)); for (int cnt = 1; cnt < 100; ++cnt) { if (sendto(listen_fd, buf, data_len, 0, (struct sockaddr *)&sin, sizeof(sin)) < 0) { cout << "system error [ " << errno << ":" << strerror(errno) << "]" << endl; cout << cnt << " failed" << endl; } else { cout << cnt << " success" << endl; } sleep(2); } cout << "Hello world!" << endl; return 0;}u_int16_t checksum(u_int16_t *buffer, int size){ u_int64_t ret = 0; while (size > 1) { ret += *buffer++; size -= 2; } if (size == 1) { ret += *((u_int8_t *)buffer); } ret = (ret >> 16) + (ret & 0xffff); ret += (ret >> 16); return (u_int16_t)(~ret);}