在RHEL 7上使用c++接收组播数据

我正在尝试在RHEL 7.2的网络接口上接收多播UDP数据

关于我的设置:网卡:Intel X540知识产权:192.168.42.100发行版:RHEL 7.2组播地址:224.5.6.7端口:2002接口名称:ens4f1

我打开了两个接口，Mobo上的1 Gbit和英特尔卡上的10 Gbit。

像许多其他的帖子，我有数据进来，并在wireshark和tcpdump可见，但我的recvfrom调用只是挂起。我的代码是这里描述的类似问题的副本，它似乎适用于OP.

指出:

1)我运行我的代码作为根

2)我试图将/proc/sys/net/ipv4/conf/ens4f1/rp_filter中的rp_filter更改为0。没有改变

3)禁用SELinux不会改变任何东西

4) Wireshark和tcpdump显示的数据很好。下面显示的转储

[@localhost ~]$ sudo tcpdump -c 5 -i ens4f1 -v
tcpdump: listening on ens4f1, link-type EN10MB (Ethernet), capture size 65535 bytes
15:43:57.368470 IP (tos 0x0, ttl 255, id 6526, offset 0, flags [DF], proto UDP (17), length 7996)
    192.168.42.44.62111 > 224.5.6.7.globe: UDP, length 7968
15:43:57.368477 IP (tos 0x0, ttl 255, id 6526, offset 0, flags [DF], proto UDP (17), length 316)
    192.168.42.44.62111 > 224.5.6.7.globe: UDP, length 288
15:43:57.368869 IP (tos 0x0, ttl 255, id 6526, offset 0, flags [DF], proto UDP (17), length 7996)
    192.168.42.44.62111 > 224.5.6.7.globe: UDP, length 7968
15:43:57.368878 IP (tos 0x0, ttl 255, id 6526, offset 0, flags [DF], proto UDP (17), length 316)
    192.168.42.44.62111 > 224.5.6.7.globe: UDP, length 288
15:43:57.369264 IP (tos 0x0, ttl 255, id 6526, offset 0, flags [DF], proto UDP (17), length 7996)
    192.168.42.44.62111 > 224.5.6.7.globe: UDP, length 7968
5 packets captured
46 packets received by filter
9 packets dropped by kernel

代码副本

#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <time.h>
#include <string.h>
#include <stdio.h>
#include <iostream>
#include <string>
using namespace std;
#define HELLO_PORT 2002
#define HELLO_GROUP "224.5.6.7"
#define MSGBUFSIZE 10000
int main(int argc, char *argv[])
{
    string source_iface("192.168.42.100");
    string group(HELLO_GROUP);
    int port(HELLO_PORT);
    cout << "group: " << group << " port: " << port << " source_iface: " << source_iface << endl;
    int fd;
    if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
    {
        perror("socket");
        exit(1);
    }
    u_int yes = 1;
    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0)
    {
        perror("Reusing ADDR failed");
        exit(1);
    }
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr =  (group.empty() ?
                            htonl(INADDR_ANY) :
                            inet_addr(group.c_str()));
    if (bind(fd,(struct sockaddr *)&addr, sizeof(addr)) < 0)
    {
        perror("bind");
        exit(1);
    }
    struct ip_mreq mreq;
    mreq.imr_multiaddr.s_addr = inet_addr(group.c_str());
    mreq.imr_interface.s_addr = (source_iface.empty() ? htonl(INADDR_ANY) : inet_addr(source_iface.c_str()));
    if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
    {
        perror("setsockopt");
        exit(1);
    }
    socklen_t addrlen;
    int nbytes;
    char msgbuf[MSGBUFSIZE];
    while (1)
    {
        memset(&msgbuf, 0, MSGBUFSIZE);
        addrlen = sizeof(addr);
        if ((nbytes = recvfrom(fd, msgbuf, MSGBUFSIZE, 0, (struct sockaddr *)&addr, &addrlen)) < 0)
        {
            perror("recvfrom");
            exit(1);
        }
        cout.write(msgbuf, nbytes);
        cout.flush();
    }
    return 0;
}

欢迎大家的帮助和建议

Henrik