Différences

Ci-dessous, les différences entre deux révisions de la page.

--- lang:c:net:client_serveur [2022/09/30 14:04] – Mise en forme pour send/recv root
+++ lang:c:net:client_serveur [2023/01/27 15:35] (Version actuelle) – [connect sous Windows] : ajout d'une source root
@@ Ligne 1: / Ligne 1: @@
 =====TCP=====
-====send/recv====
+====connect sous Windows====
+Pour ne pas avoir de connect bloquant et maitriser le timeout, on peut utiliser le code suivant :
+<code c>
+int error = -1;
+int len = sizeof(int);
+timeval tm;
+fd_set set;
+unsigned long ul = 1;
+ioctlsocket(Socket, FIONBIO, &ul);  // set as non-blocking
+bool ret = false;
+if (connect(Socket, (struct sockaddr *)&ServerAddress,
+      sizeof(ServerAddress)) == -1) {
+  tm.tv_sec = 10;  // set the timeout. 10s
+  tm.tv_usec = 0;
+  FD_ZERO(&set);
+  FD_SET(Socket, &set);
+  if (select(Socket + 1, NULL, &set, NULL, &tm) > 0) {
+    getsockopt(Socket, SOL_SOCKET, SO_ERROR, (char *)&error,
+           /*(socklen_t *)*/ &len);
+    if (error == 0)
+      ret = true;
+    else
+      ret = false;
+  } else
+    ret = false;
+} else
+  ret = true;
+ul = 0;
+ioctlsocket(Socket, FIONBIO, &ul);  // set as blocking
+if (!ret) {
+  closesocket(Socket);
+  fprintf(stderr, "Cannot Connect the server!/n");
+}
+</code>
+[[https://social.msdn.microsoft.com/Forums/en-US/2202d113-212d-420d-9e7b-11268de9ce90/win32-tcp-connect-timeout|Win32: TCP connect timeout]] {{ :lang:c:net:win32_tcp_connect_timeout_27_01_2023_15_32_49_.html |Archive du 24/08/2018 le 27/01/2023}}
+====send/recv sous Linux====
 <WRAP center round important 60%>
@@ Ligne 186: / Ligne 226: @@
 }
 </file>
+====sendmsg/recvmsg sous Linux====
+Transfert d'un file descripteur via socket Unix.
+<WRAP center round important 60%>
+Il faut passer par un fichier temporaire. Je n'ai pas réussi à transposer le code par des ports TCP/IP.
+</WRAP>
+===Serveur===
+<code c>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#define SOCK_PATH "/tmp/usocket"
+int send_msg_to_client(int socketfd, int fd) {
+  struct msghdr msg;
+  struct iovec iov;
+  int s;
+  char buf[CMSG_SPACE(sizeof(fd))];
+  memset(&msg, 0, sizeof(msg));
+  memset(&iov, 0, sizeof(iov));
+  msg.msg_name = NULL;
+  msg.msg_namelen = 0;
+  iov.iov_base = "";
+  iov.iov_len = 1;
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+  msg.msg_control = buf;
+  msg.msg_controllen = sizeof(buf);
+  msg.msg_flags = 0;
+  struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+  cmsg->cmsg_level = SOL_SOCKET;
+  cmsg->cmsg_type = SCM_RIGHTS;
+  cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
+  memmove(CMSG_DATA(cmsg), &fd, sizeof(fd));
+  msg.msg_controllen = CMSG_SPACE(sizeof(fd));
+  s = sendmsg(socketfd, &msg, 0);
+  if (s < 0) {
+    perror("sendmsg");
+    return 0;
+  }
+  return s;
+}
+int main(int argc, char *argv[]) {
+  int s, s2, len, slen;
+  socklen_t t;
+  struct sockaddr_un local, remote;
+  if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
+    perror("socket");
+    exit(1);
+  }
+  local.sun_family = AF_UNIX;
+  strcpy(local.sun_path, SOCK_PATH);
+  unlink(local.sun_path);
+  len = strlen(local.sun_path) + sizeof(local.sun_family);
+  if (bind(s, (struct sockaddr *)&local, len) == -1) {
+    perror("bind");
+    exit(1);
+  }
+  if (listen(s, 5) == -1) {
+    perror("listen");
+    exit(1);
+  }
+  printf("Waiting for a connection...\n");
+  t = sizeof(remote);
+  if ((s2 = accept(s, (struct sockaddr *)&remote, &t)) == -1) {
+    perror("accept");
+    exit(1);
+  }
+  printf("Connected.\n");
+  int fd = open("./z7.c", O_RDONLY);
+  if (fd < 0)
+    printf("Parent Failed to open file %s for reading\n", "./z7.c");
+  slen = send_msg_to_client(s2, fd);
+  if (slen < 0)
+    perror("send");
+  printf("sent data length: %d\n", slen);
+  close(s2);
+  return 0;
+}
+</code>
+===Client===
+<code c>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#define SOCK_PATH "/tmp/usocket"
+int recv_msg_from_server(int socketfd) {
+  struct msghdr msg = {0};
+  /* On Mac OS X, the struct iovec is needed, even if it points to minimal data
+   */
+  char m_buffer[1];
+  struct iovec io = {.iov_base = m_buffer, .iov_len = sizeof(m_buffer)};
+  msg.msg_iov = &io;
+  msg.msg_iovlen = 1;
+  char c_buffer[256];
+  msg.msg_control = c_buffer;
+  msg.msg_controllen = sizeof(c_buffer);
+  if (recvmsg(socketfd, &msg, 0) < 0)
+    printf("Child Failed to receive message\n");
+  struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+  printf("Child About to extract fd\n");
+  int fd;
+  memmove(&fd, CMSG_DATA(cmsg), sizeof(fd));
+  printf("Child Extracted fd %d\n", fd);
+  return fd;
+}
+int main(void) {
+  int s, len, slen;
+  struct sockaddr_un remote;
+  if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
+    perror("socket");
+    exit(1);
+  }
+  printf("Trying to connect...\n");
+  remote.sun_family = AF_UNIX;
+  strcpy(remote.sun_path, SOCK_PATH);
+  len = strlen(remote.sun_path) + sizeof(remote.sun_family);
+  if (connect(s, (struct sockaddr *)&remote, len) == -1) {
+    perror("connect");
+    exit(1);
+  }
+  printf("Connected.\n");
+  slen = recv_msg_from_server(s);
+  char buffer[256];
+  int nbytes;
+  if ((nbytes = read(slen, buffer, sizeof(buffer))) > 0) {
+    printf("Child read: [[%.*s]]\n", nbytes, buffer);
+  }
+  close(s);
+  return 0;
+}
+</code>
 =====UDP=====