一文解析LINUX中的socket与VRF

#!/bin/bash sudo ip netns add ns1  sudo ip link add ns1veth1 type veth peer name eth0 netns ns1 sudo ip netns add ns2 sudo ip link add ns2veth1 type veth peer name eth0 netns ns2 sudo ip link set ns1veth1 master vrftest sudo ip link set ns2veth1 master vrftest sudo ip link set ns2veth1 up sudo ip link set ns1veth1 up sudo ip addr add 1.1.1.254/24 dev ns1veth1  sudo ip addr add 2.2.2.254/24 dev ns2veth1  sudo ip netns exec ns2 ip addr add 2.2.2.1/24 dev eth0  sudo ip netns exec ns1 ip addr add 1.1.1.1/24 dev eth0  sudo ip netns exec ns1 ip link set eth0 up sudo ip netns exec ns1 ip link set lo up sudo ip netns exec ns1 ip route add default via 1.1.1.254 dev eth0 sudo ip netns exec ns2 ip link set eth0 up sudo ip netns exec ns2 ip link set lo up sudo ip netns exec ns2 ip route add default via 2.2.2.254 dev eth0

#include<stdio.h> #include<stdlib.h> #include<string.h> #include<errno.h> #include<sys/types.h> #include<sys/socket.h> #include<netinet/in.h> #include <unistd.h>  #define MAXLINE 4096  int main(int argc, char** argv) {     int    listenfd, connfd;     struct sockaddr_in     servaddr;     char    buff[4096];     int     n;     int     on = 1;        if( (listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ){         printf("create socket error: %s(errno: %d)n",strerror(errno),errno);         exit(0);     }     setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, (void *)&on,                          sizeof(on));     setsockopt(listenfd, SOL_SOCKET, SO_REUSEPORT, (void *)&on,                          sizeof(on));      memset(&servaddr, 0, sizeof(servaddr));     servaddr.sin_family = AF_INET;     servaddr.sin_addr.s_addr = htonl(INADDR_ANY);     servaddr.sin_port = htons(6666);      if(argc == 2){         printf("vrf device name: %srn", argv[1]);         if(0 > setsockopt(listenfd, SOL_SOCKET, SO_BINDTODEVICE, argv[1], strlen(argv[1])+1)){              printf("bind socket master dev error: %s(errno: %d)n",strerror(errno),errno);              exit(0);         }     }      if( bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1){         printf("bind socket error: %s(errno: %d)n",strerror(errno),errno);         exit(0);     }      if( listen(listenfd, 10) == -1){         printf("listen socket error: %s(errno: %d)n",strerror(errno),errno);         exit(0);     }      printf("======waiting for client's request======n");     while(1){         if((connfd = accept(listenfd, (struct sockaddr*)NULL, NULL)) == -1){                 printf("accept socket error: %s(errno: %d)",strerror(errno),errno);                 continue;         }         n = recv(connfd, buff, MAXLINE, 0);         buff[n] = '';         printf("recv msg from client: %sn", buff);         close(connfd);     }      close(listenfd); }

#include<stdio.h> #include<stdlib.h> #include<string.h> #include<errno.h> #include<sys/types.h> #include<sys/socket.h> #include<netinet/in.h> #include<unistd.h> #define MAXLINE 4096 #include <arpa/inet.h>  int main(int argc, char** argv) {     int    sockfd, n;     char   *sendline = "hello vrf";     struct sockaddr_in    servaddr;      if( argc != 2){     printf("usage: ./client <ipaddress> [master device]n");     exit(0);     }      if( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){     printf("create socket error: %s(errno: %d)n", strerror(errno),errno);     exit(0);     }      memset(&servaddr, 0, sizeof(servaddr));     servaddr.sin_family = AF_INET;     servaddr.sin_port = htons(6666);     if( inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0){     printf("inet_pton error for %sn",argv[1]);     exit(0);     }      if(argc == 3){         printf("vrf device name: %srn", argv[2]);         if(0 > setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, argv[2], strlen(argv[2])+1)){              printf("bind socket master dev error: %s(errno: %d)n",strerror(errno),errno);              exit(0);         }     }     if( connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0){     printf("connect error: %s(errno: %d)n",strerror(errno),errno);     exit(0);     }      printf("send msg to server: hello vrfn");          if( send(sockfd, sendline, strlen(sendline), 0) < 0)     {     printf("send msg error: %s(errno: %d)n", strerror(errno), errno);     exit(0);     }      close(sockfd);     exit(0); }

admin@ubuntu:~/vrfsocket$ for i in {0..9}; do ./vrfc 127.0.0.1; done   send msg to server: hello vrf send msg to server: hello vrf send msg to server: hello vrf send msg to server: hello vrf send msg to server: hello vrf send msg to server: hello vrf send msg to server: hello vrf send msg to server: hello vrf send msg to server: hello vrf send msg to server: hello vrf admin@ubuntu:~/vrfsocket$

admin@ubuntu:~/vrfsocket$ ./vrfs  ======waiting for client's request====== recv msg from client: hello vrf recv msg from client: hello vrf recv msg from client: hello vrf recv msg from client: hello vrf recv msg from client: hello vrf recv msg from client: hello vrf recv msg from client: hello vrf

admin@ubuntu:~/vrfsocket$ ./vrfs  ======waiting for client's request====== recv msg from client: hello vrf recv msg from client: hello vrf recv msg from client: hello vrf

root@ubuntu:/home/admin/vrfsocket# ./vrfs ======waiting for client's request======

admin@ubuntu:~/vrfsocket$ for i in {0..9}; do sudo ./vrfc 127.0.0.1; done connect error: Connection refused(errno: 111) connect error: Connection refused(errno: 111) connect error: Connection refused(errno: 111) connect error: Connection refused(errno: 111) connect error: Connection refused(errno: 111) connect error: Connection refused(errno: 111) connect error: Connection refused(errno: 111) connect error: Connection refused(errno: 111) connect error: Connection refused(errno: 111) connect error: Connection refused(errno: 111) admin@ubuntu:~/vrfsocket$