西厢2服务器

wcs2_fwd.c

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>


void socket_iphdrincl(int sd)
{
        const int one = 1;

        if (setsockopt(sd, IPPROTO_IP, IP_HDRINCL,
                                (char *)&one, sizeof(one)) == -1)
        {
                perror("setsockopt");
                exit(1);
        }
}

int main(int argc, char *argv[])
{
        if (argc != 2)
        {
                printf("Usage: %s PORT\n", argv[0]);
                exit(1);
        }
        int sock_udp = socket(AF_INET, SOCK_DGRAM, 0);
        if (sock_udp == -1) {
                perror("socket");
                exit(1);
        }
        int sock_raw = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
        if (sock_raw == -1) {
                perror("socket");
                exit(1);
        }
        socket_iphdrincl(sock_raw);

        struct sockaddr_in local = {0};
        local.sin_family=AF_INET;
        local.sin_port=htons(atoi(argv[1])); 
        local.sin_addr.s_addr=INADDR_ANY;

        bind(sock_udp,(struct sockaddr*)&local,sizeof(local));

        struct sockaddr_in sa = {0};
        sa.sin_family = AF_INET;

        int total = 0;
        while (1) {
                unsigned char buf[2048];
                int len = recv(sock_udp, buf, sizeof(buf), 0);
                printf("forward packet, size = %d, total = %d KB\n", len, (total += len) / 1024);
                int i;
                for (i=0; i<len; i++)
                        buf[i] ^= 0x5a;
                sa.sin_addr.s_addr = *(unsigned int *)&buf[16];
                sendto(sock_raw, buf, len, 0, (struct sockaddr*)&sa, sizeof(sa));
        }
        return 0;
}