【转】TCP粘包问题解决方法之\n\r

该方案，每次读取时当读到‘\n’换行符时，读取该行

服务器端：

 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #define ERR_EXIT(m) do{perror(m);exit(EXIT_FAILURE);}while(1)
 struct packet
 {
     int len;
     char buf[1024];
 };
 ssize_t readn(int fd, void *buf, size_t count)
 {
     size_t nleft = count;
     ssize_t nread;
     char *bufp = (char*)buf;
     while (nleft > 0)
     {
         if ((nread = read(fd, bufp, nleft)) < 0)
         {
             if (errno == EINTR)
             {
                 continue;
                 return -1;
             }
             else if (nread == 0)return count - nleft;
         }
         bufp = bufp + nread;
         nleft = nleft - nread;
     }
     return count;
 }
 ssize_t writen(int fd, void *buf, size_t count)
 {
     size_t nleft = count;
     ssize_t nwrite;
     char *bufp = (char*)buf;
     while (nleft > 0)
     {
         if ((nwrite = write(fd, bufp, nleft)) < 0)
         {
             if (errno == EINTR)
             {
                 continue;
                 return -1;
             }
             else if (nwrite == 0)continue;
         }
         bufp = bufp + nwrite;
         nleft = nleft - nwrite;
     }
     return count;
 }
 ssize_t recv_peek(int sockfd, void *buf, size_t len)
 {
     while (1)
     {
         int ret = recv(sockfd, buf, len, MSG_PEEK);
         if (ret == -1 && errno == EINTR)continue;
         return ret;
     }
 }
 ssize_t readline(int sockfd, void *buf, size_t maxline)
 {
     int ret;
     int nread;
     char *bufp = (char*)buf;
     int nleft = maxline;
     while (1)
     {
         ret = recv_peek(sockfd, bufp, nleft);
         if (ret < 0)return ret;
         else if (ret == 0)return ret;//对方关闭了套接口
         nread = ret;
         for (int i = 0; i < nread; i++)
         {
             if (bufp[i] == '\n')
             {
                 ret = readn(sockfd, bufp, i + 1);//将缓冲区数据移除
                 if (ret != i + 1)exit(EXIT_FAILURE);
                 return ret;
             }
         }
         if (nread>nleft)exit(EXIT_FAILURE);//读到的数据不能超过缓冲区
         nleft -= nread;
         ret = readn(sockfd, bufp, nread);
         if (ret != nread)exit(EXIT_FAILURE);
         bufp += nread;
     }
     return -1;
 }
 void do_service(int connfd)
 {
     char recvbuf[1024];
     int n;
     while (1)
     {
         memset(&recvbuf, 0, sizeof(recvbuf));
         int ret = readline(connfd, recvbuf, 1204);
         if (ret == -1)
         {
             ERR_EXIT("read");
         }
         else if (ret ==0 )
         {
             printf("client cloase\n");
             break;
         }
         fputs(recvbuf, stdout);
         writen(connfd, recvbuf, strlen(recvbuf));
     }
 }
 int main(void)
 {
     int listenfd;
     if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)ERR_EXIT("socket");
     struct sockaddr_in servaddr;
     memset(&servaddr, 0, sizeof(servaddr));
     servaddr.sin_family = AF_INET;
     servaddr.sin_port = htons(5188);
     servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
     int on = 1;
     if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0)ERR_EXIT("setsockopt");
     if (bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0)ERR_EXIT("bind");
     if (listen(listenfd, SOMAXCONN) < 0)ERR_EXIT("listten");
     while (1)
     {
         int connfd;
         struct sockaddr_in peeraddr;
         socklen_t peerlen = sizeof(peeraddr);
         if ((connfd = accept(listenfd, (struct sockaddr*)&peeraddr, &peerlen)) < 0)ERR_EXIT("accept");
             printf("ip=%s port=%d\n", inet_ntoa(peeraddr.sin_addr), ntohs(peeraddr.sin_port));
             pid_t pid = fork();
         if (pid == -1)ERR_EXIT("fork");
         if (pid == 0)
         {
             close(listenfd);
             do_service(connfd);
             exit(EXIT_SUCCESS);
         }
         if (pid > 0)
         {
             close(connfd);
         }
     }
     close(listenfd);
 }

客户端：

 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #define ERR_EXIT(m) do{perror(m);exit(EXIT_FAILURE);}while(1)
 struct packet
 {
     int len;
     char buf[1024];
 };
 ssize_t readn(int fd, void *buf, size_t count)
 {
     size_t nleft = count;
     ssize_t nread;
     char *bufp = (char*)buf;
     while (nleft > 0)
     {
         if ((nread = read(fd, bufp, nleft)) < 0)
         {
             if (errno == EINTR)
             {
                 continue;
                 return -1;
             }
             else if (nread == 0)return count - nleft;
         }
         bufp = bufp + nread;
         nleft = nleft - nread;
     }
     return count;
 }
 ssize_t writen(int fd, void *buf, size_t count)
 {
     size_t nleft = count;
     ssize_t nwrite;
     char *bufp = (char*)buf;
     while (nleft > 0)
     {
         if ((nwrite = write(fd, bufp, nleft)) < 0)
         {
             if (errno == EINTR)
             {
                 continue;
                 return -1;
             }
             else if (nwrite == 0)continue;
         }
         bufp = bufp + nwrite;
         nleft = nleft - nwrite;
     }
     return count;
 }
 ssize_t recv_peek(int sockfd, void *buf, size_t len)
 {
     while (1)
     {
         int ret = recv(sockfd, buf, len, MSG_PEEK);
         if (ret == -1 && errno == EINTR)continue;
         return ret;
     }
 }
 ssize_t readline(int sockfd, void *buf, size_t maxline)
 {
     int ret;
     int nread;
     char *bufp = (char*)buf;
     int nleft = maxline;
     while (1)
     {
         ret = recv_peek(sockfd, bufp, nleft);
         if (ret < 0)return ret;
         else if (ret == 0)return ret;//对方关闭了套接口
         nread = ret;
         for (int i = 0; i < nread; i++)
         {
             if (bufp[i] == '\n')
             {
                 ret = readn(sockfd, bufp, i + 1);//将缓冲区数据移除
                 if (ret != i + 1)exit(EXIT_FAILURE);
                 return ret;
             }
         }
         if (nread>nleft)exit(EXIT_FAILURE);//读到的数据不能超过缓冲区
         nleft -= nread;
         ret = readn(sockfd, bufp, nread);
         if (ret != nread)exit(EXIT_FAILURE);
         bufp += nread;
     }
     return -1;
 }

 int main(void)
 {
     int sockfd;
     if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)ERR_EXIT("socket");
     struct sockaddr_in servaddr;
     memset(&servaddr, 0, sizeof(servaddr));
     servaddr.sin_family = AF_INET;
     servaddr.sin_port = htons(5188);
     servaddr.sin_addr.s_addr = inet_addr("127.0.1");
     if (connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0)ERR_EXIT("bind");
     char sendbuf[1024];
     char recvbuf[1024];
     memset(sendbuf, 0, sizeof(sendbuf));
     memset(recvbuf, 0, sizeof(recvbuf));
     while (fgets(sendbuf, sizeof(sendbuf), stdin) != NULL)
     {
         writen(sockfd, sendbuf, strlen(sendbuf));
         int ret = readline(sockfd, recvbuf, sizeof(recvbuf));
         if (ret == -1)ERR_EXIT("read");
         if (ret == 0)
         {
             printf("server close\n");
             break;
         }
         fputs(recvbuf, stdout);
         memset(sendbuf, 0, sizeof(sendbuf));
         memset(recvbuf, 0, sizeof(recvbuf));
     }
     close(sockfd);
 }