我有这个c可执行文件负责处理数据包。
我正在尝试使用setsockopt将接口绑定到我的套接字sockfd
#define MULTICAST
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/time.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <time.h>
#include <sys/ioctl.h>
#include <net/if.h>
#define TS_PACKET_SIZE 188
long long int usecDiff(struct timeval* time_stop, struct timeval* time_start)
{
long long int temp = 0;
long long int utemp = 0;
if (time_stop && time_start) {
if (time_stop->tv_usec >= time_start->tv_usec) {
utemp = time_stop->tv_usec - time_start->tv_usec;
temp = time_stop->tv_sec - time_start->tv_sec;
} else {
utemp = time_stop->tv_usec + 1000000 - time_start->tv_usec;
temp = time_stop->tv_sec - 1 - time_start->tv_sec;
}
if (temp >= 0 && utemp >= 0) {
temp = (temp * 1000000) + utemp;
} else {
fprintf(stderr, "start time %ld.%ld is after stop time %ld.%ld\n", time_start->tv_sec, time_start->tv_usec, time_stop->tv_sec, time_stop->tv_usec);
temp = -1;
}
} else {
fprintf(stderr, "memory is garbaged?\n");
temp = -1;
}
return temp;
}
int main (int argc, char *argv[]) {
int sockfd;
int len;
int sent;
int transport_fd;
struct sockaddr_in addr;
unsigned long int packet_size;
char* tsfile;
unsigned char* send_buf;
unsigned int bitrate;
unsigned long long int packet_time;
unsigned long long int real_time;
struct timeval time_start;
struct timeval time_stop;
struct timespec nano_sleep_packet;
char *opt; // "eth0" or "eth1"
memset(&addr, 0, sizeof(addr));
memset(&time_start, 0, sizeof(time_start));
memset(&time_stop, 0, sizeof(time_stop));
memset(&nano_sleep_packet, 0, sizeof(nano_sleep_packet));
if(argc < 6 ) {
fprintf(stderr, "Usage: %s file.ts ipaddr port bitrate [ts_packet_per_ip_packet]\n", argv[0]);
fprintf(stderr, "ts_packet_per_ip_packet default is 7\n");
fprintf(stderr, "bit rate refers to transport stream bit rate\n");
fprintf(stderr, "zero bitrate is 100.000.000 bps\n");
fprintf(stderr, "This is the modified file\n");
return 0;
} else {
tsfile = argv[1];
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = inet_addr(argv[2]);
addr.sin_port = htons(atoi(argv[3]));
bitrate = atoi(argv[4]);
opt = argv[5];
if (bitrate <= 0) {
bitrate = 100000000;
}
//To be modified : original arguments are 5 and have to be increased by one
if (argc >= 7) {
packet_size = strtoul(argv[5], 0, 0) * TS_PACKET_SIZE;
} else {
packet_size = 7 * TS_PACKET_SIZE;
}
}
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if(sockfd < 0) {
perror("socket(): error ");
return 0;
}
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
//snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), opt); //
setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, opt, strlen(opt)); // 6 is the size of MAC address in bytes
ioctl(sockfd, SIOCGIFINDEX, &ifr);
if (setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr)) < 0) {
perror("Server-setsockopt() error for SO_BINDTODEVICE");
close(sockfd);
return 0;
}
transport_fd = open(tsfile, O_RDONLY);
if(transport_fd < 0) {
fprintf(stderr, "can't open file %s\n", tsfile);
close(sockfd);
return 0;
}
int completed = 0;
send_buf = malloc(packet_size);
packet_time = 0;
real_time = 0;
gettimeofday(&time_start, 0);
while (!completed) {
gettimeofday(&time_stop, 0);
real_time = usecDiff(&time_stop, &time_start);
if (real_time * bitrate > packet_time * 1000000) { /* theorical bits against sent bits */
len = read(transport_fd, send_buf, packet_size);
if(len < 0) {
fprintf(stderr, "ts file read error \n");
completed = 1;
} else if (len == 0) {
fprintf(stderr, "ts sent done\n");
completed = 1;
} else {
sent = sendto(sockfd, send_buf, len, 0, (struct sockaddr *)&addr, sizeof(struct sockaddr_in));
if(sent <= 0) {
perror("send(): error ");
completed = 1;
} else {
packet_time += packet_size * 8;
}
}
} else {
nanosleep(&nano_sleep_packet, 0);
}
}
close(transport_fd);
close(sockfd);
free(send_buf);
return 0;
}
我在Python脚本中使用subprocess.Popen（）调用此文件，如下所示
self.proc.append(subprocess.Popen(["tsudpsend", "/dev/stdin", out_address, str(port), "10000000", "eth0"], stdin=self.proc[-1].stdout, stderr=open("/home/cayman/log.txt", "w")))
当我检查管道输出时，我发现以下错误：
SO_BINDTODEVICE的Server-setsockopt（）错误：不允许操作
我花了一些时间研究this thread，我看到了一些建议，但徒劳无功。任何人都可以指导我如何解决这个问题。 感谢。
答案 0 :(得分：1)
SO_BINDTODEVICE的问题在于您必须是root才能使用它。如果我以root身份运行您的代码，我就不会收到该错误。
您需要做的是通过getifaddrs获取接口列表并循环访问接口列表，直到名称与您想要的名称匹配。然后，您提取有问题的IPv4地址，然后使用该地址填充sockaddr_in来电中的bind。
struct sockaddr_in bind_addr;
memset(&bind_addr, 0, sizeof(bind_addr);
bind_addr.sin_family = AF_INET;
bind_addr.sin_port = htons(atoi(argv[3]));
...
struct ifaddrs *ifa, *ifa_tmp;
if (getifaddrs(&ifa) == -1) {
perror("getifaddrs failed");
exit(1);
}
ifa_tmp = ifa;
while (ifa_tmp) {
if (!strcmp(ifa_tmp->ifa_name, opt) &&
ifa_tmp->ifa_addr && (ifa_tmp->ifa_addr->sa_family == AF_INET)) {
printf("addr = %s\n",
inet_ntoa(((struct sockaddr_in *)ifa_tmp->ifa_addr)->sin_addr);
bind_addr.sin_addr.s_addr =
((struct sockaddr_in *)ifa_tmp->ifa_addr)->sin_addr.s_addr;
break;
}
ifa_tmp = ifa_tmp->ifa_next;
}
freeifaddrs(ifa);
if (bind_addr.sin_addr.s_addr == 0) {
printf("interface not found\n");
exit(1);
}
...
if (bind(sockfd, (struct sockaddr *)&bind_addr, sizeof(bind_addr)) != 0) {
perror("bind failed");
exit(1);
}
...
答案 1 :(得分：0)
准确地说，您需要CAP_NET_RAW功能。