From ea435789dc2fab30ec16fa765a0b6577fe08166a Mon Sep 17 00:00:00 2001
From: GuoWenxue <“guowenxue@gmail.com”>
Date: Tue, 19 Apr 2022 10:06:03 +0800
Subject: [PATCH] update client and socket.c, add DNS support
---
apue/project_socket/src/socket.c | 188 +++++++++++++++++++++++++++++-----------------
1 files changed, 118 insertions(+), 70 deletions(-)
diff --git a/apue/project_socket/src/socket.c b/apue/project_socket/src/socket.c
index 9de6d1a..677a3cc 100644
--- a/apue/project_socket/src/socket.c
+++ b/apue/project_socket/src/socket.c
@@ -8,7 +8,7 @@
* Version: 1.0.0(18/04/22)
* Author: Guo Wenxue <guowenxue@gmail.com>
* ChangeLog: 1, Release initial version on "18/04/22 17:09:59"
- *
+ *
********************************************************************************/
#include <stdio.h>
#include <unistd.h>
@@ -18,7 +18,7 @@
#include <unistd.h>
#include <sys/un.h>
#include <poll.h>
-#include <errno.h>
+#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <linux/sockios.h>
@@ -32,8 +32,8 @@
#include "socket.h"
#include "logger.h"
-/* description: initial socket context
- * input args:
+/* description: initial socket context
+ * input args:
* $sock: socket context pointer
* $host: connect server hostname for client mode, unused for server mode
* $port: connect server port for client mode or listen port for server mode
@@ -51,7 +51,7 @@
}
/* description: close socket
- * input args:
+ * input args:
* $sock: socket context pointer
* return value: <0: failure 0:ok
*/
@@ -70,66 +70,114 @@
}
/* description: socket server start listen
- * input args:
+ * input args:
* $sock: socket context pointer
* return value: <0: failure 0:ok
*/
int socket_listen(socket_ctx_t *sock)
{
- int rv = 0;
+ int rv = 0;
struct sockaddr_in addr;
- int backlog = 13;
+ int backlog = 13;
if( !sock )
return -1;
}
-/* description: socket check connected or not
- * input args:
+/* description: socket connect to server in block mode
+ * input args:
* $sock: socket context pointer
* return value: <0: failure 0:ok
*/
int socket_connect(socket_ctx_t *sock)
{
- int rv = 0;
- int sockfd = 0;
+ int rv = 0;
+ int sockfd = 0;
struct sockaddr_in servaddr;
+ char service[20];
+ struct addrinfo hints, *rp;
+ struct addrinfo *res = NULL;
+ struct in_addr inaddr;
+ struct sockaddr_in addr;
+ int len = sizeof(addr);
if( !sock )
return -1;
socket_term(sock);
- sockfd = socket(AF_INET, SOCK_STREAM, 0);
- if(sockfd < 0)
- {
- log_error("create socket failure: %s\n", strerror(errno));
- return -1;
- }
+ /*+--------------------------------------------------+
+ *| use getaddrinfo() to do domain name translation |
+ *+--------------------------------------------------+*/
- memset(&servaddr, 0, sizeof(servaddr));
- servaddr.sin_family=AF_INET;
- servaddr.sin_port = htons(sock->port);
- inet_aton(sock->host, &servaddr.sin_addr);
+ memset(&hints, 0, sizeof(struct addrinfo));
+ hints.ai_family = AF_INET; /* Only support IPv4 */
+ hints.ai_socktype = SOCK_STREAM;
+ hints.ai_protocol = IPPROTO_TCP; /* TCP protocol */
- rv=connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
- if(rv < 0)
- {
- //log_error("connect to server[%s:%d] failure: %s\n", sock->host, sock->port, strerror(errno));
- close(sockfd);
- return -2;
- }
+ /* If $host is a valid IP address, then don't use name resolution */
+ if( inet_aton(sock->host, &inaddr) )
+ {
+ //log_info("%s is a valid IP address, don't use domain name resolution.\n", sock->host);
+ hints.ai_flags |= AI_NUMERICHOST;
+ }
- log_info("Connect to server[%s:%d] on fd[%d] successfully!\n", sock->host, sock->port, sockfd);
+ /* Obtain address(es) matching host/port */
+ snprintf(service, sizeof(service), "%d", sock->port);
+ if( (rv=getaddrinfo(sock->host, service, &hints, &res)) )
+ {
+ log_error("getaddrinfo() parser [%s:%s] failed: %s\n", sock->host, service, gai_strerror(rv));
+ return -3;
+ }
- sock->fd = sockfd;
+ /* getaddrinfo() returns a list of address structures. Try each
+ address until we successfully connect or bind */
+ for (rp=res; rp!=NULL; rp=rp->ai_next)
+ {
+#if 0
+ char ipaddr[INET_ADDRSTRLEN];
+ struct sockaddr_in *sp = (struct sockaddr_in *) rp->ai_addr;
- return 0;
+ /* print domain name translation result */
+ memset( ipaddr, 0, sizeof(ipaddr) );
+ if( inet_ntop(AF_INET, &sp->sin_addr, ipaddr, sizeof(ipaddr)) )
+ {
+ log_info("domain name resolution [%s->%s]\n", sock->host, ipaddr);
+ }
+#endif
+
+ /* Create the socket */
+ sockfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+ if( sockfd < 0)
+ {
+ log_error("socket() create failed: %s\n", strerror(errno));
+ rv = -3;
+ continue;
+ }
+
+ /* connect to server */
+ rv = connect(sockfd, rp->ai_addr, len);
+ if( 0 == rv )
+ {
+ sock->fd = sockfd;
+ log_info("Connect to server[%s:%d] on fd[%d] successfully!\n", sock->host, sock->port, sockfd);
+ break;
+ }
+ else
+ {
+ /* socket connect get error, try another IP address */
+ close(sockfd);
+ continue;
+ }
+ }
+
+ freeaddrinfo(res);
+ return rv;
}
/* description: send data from the socket
- * input args:
+ * input args:
* $sock : socket context pointer
* $data : socket send data
* $bytes: socket send data bytes
@@ -144,32 +192,32 @@
if( !sock || !data || bytes<= 0 )
return -1;
- while( left_bytes > 0 )
- {
+ while( left_bytes > 0 )
+ {
rv=write(sock->fd, &data[i], left_bytes);
- if( rv < 0 )
+ if( rv < 0 )
{
log_info("socket[%d] write() failure: %s, close socket now\n", sock->fd, strerror(errno));
socket_term(sock);
- return -2;
+ return -2;
}
else if( rv == left_bytes )
{
log_info("socket send %d bytes data over\n", bytes);
return 0;
}
- else
+ else
{
/* not send over this time, continue to send left data */
- i += rv;
- left_bytes -= rv;
+ i += rv;
+ left_bytes -= rv;
continue;
}
- }
+ }
}
/* description: receive data from the socket
- * input args:
+ * input args:
* $sock : socket context pointer
* $buf : socket receive data buffer
* $size : socket receive data buffer size
@@ -278,30 +326,30 @@
{
int opts;
/*
- * fcntl may set:
+ * fcntl may set:
*
- * EACCES, EAGAIN: Operation is prohibited by locks held by other
- * processes. Or, operation is prohibited because the file has
- * been memory-mapped by another process.
- * EBADF: fd is not an open file descriptor, or the command was F_SETLK
- * or F_SETLKW and the file descriptor open mode doesn't match
+ * EACCES, EAGAIN: Operation is prohibited by locks held by other
+ * processes. Or, operation is prohibited because the file has
+ * been memory-mapped by another process.
+ * EBADF: fd is not an open file descriptor, or the command was F_SETLK
+ * or F_SETLKW and the file descriptor open mode doesn't match
* with the type of lock requested.
- * EDEADLK: It was detected that the specified F_SETLKW command would
+ * EDEADLK: It was detected that the specified F_SETLKW command would
* cause a deadlock.
* EFAULT: lock is outside your accessible address space.
- * EINTR: For F_SETLKW, the command was interrupted by a signal. For
- * F_GETLK and F_SETLK, the command was interrupted by a signal
- * before the lock was checked or acquired. Most likely when
- * locking a remote file (e.g. locking over NFS), but can
+ * EINTR: For F_SETLKW, the command was interrupted by a signal. For
+ * F_GETLK and F_SETLK, the command was interrupted by a signal
+ * before the lock was checked or acquired. Most likely when
+ * locking a remote file (e.g. locking over NFS), but can
* sometimes happen locally.
- * EINVAL: For F_DUPFD, arg is negative or is greater than the maximum
- * allowable value. For F_SETSIG, arg is not an allowable signal
+ * EINVAL: For F_DUPFD, arg is negative or is greater than the maximum
+ * allowable value. For F_SETSIG, arg is not an allowable signal
* number.
- * EMFILE: For F_DUPFD, the process already has the maximum number of
- * file descriptors open.
- * ENOLCK: Too many segment locks open, lock table is full, or a remote
+ * EMFILE: For F_DUPFD, the process already has the maximum number of
+ * file descriptors open.
+ * ENOLCK: Too many segment locks open, lock table is full, or a remote
* locking protocol failed (e.g. locking over NFS).
- * EPERM: Attempted to clear the O_APPEND flag on a file that has the
+ * EPERM: Attempted to clear the O_APPEND flag on a file that has the
* append-only attribute set.
*/
opts = fcntl(sockfd, F_GETFL);
@@ -377,7 +425,7 @@
* Enable socket SO_KEEPALIVE, if the connection disconnected, any system call on socket
* will return immediately and errno will be set to "WSAENOTCONN"
*
- * keepalive is not program related, but socket related, * so if you have multiple sockets,
+ * keepalive is not program related, but socket related, * so if you have multiple sockets,
* you can handle keepalive for each of them separately.
*
* Reference: http://tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/
@@ -400,10 +448,10 @@
if(keepintvl || keepcnt)
{
/*
- * The tcp_keepidle parameter specifies the interval between the last data packet sent
- * (simple ACKs are not considered data) and the first keepalive probe; after the
- * connection is marked to need keepalive, this counter is not used any further.
- * ~ >: cat /proc/sys/net/ipv4/tcp_keepalive_time
+ * The tcp_keepidle parameter specifies the interval between the last data packet sent
+ * (simple ACKs are not considered data) and the first keepalive probe; after the
+ * connection is marked to need keepalive, this counter is not used any further.
+ * ~ >: cat /proc/sys/net/ipv4/tcp_keepalive_time
* 7200
*/
opt = 3; /* 3 seconds */
@@ -416,9 +464,9 @@
if((opt=keepintvl) > 0)
{
/*
- * The tcp_keepintvl parameter specifies the interval between subsequential keepalive
+ * The tcp_keepintvl parameter specifies the interval between subsequential keepalive
* probes, regardless of what the connection has exchanged in the meantime.
- * ~ >: cat /proc/sys/net/ipv4/tcp_keepalive_intvl
+ * ~ >: cat /proc/sys/net/ipv4/tcp_keepalive_intvl
* 75
*/
if (setsockopt (sockfd, SOL_TCP, TCP_KEEPINTVL, (char *) &opt, sizeof (opt)))
@@ -431,11 +479,11 @@
if((opt=keepcnt) > 0)
{
/*
- * The TCP_KEEPCNT option specifies the maximum number of unacknowledged probes to
+ * The TCP_KEEPCNT option specifies the maximum number of unacknowledged probes to
* send before considering the connection dead and notifying the application layer
- * probes to be sent. The value of TCP_KEEPCNT is an integer value between 1 and n,
- * where n is the value of the systemwide tcp_keepcnt parameter.
- * ~ >: cat /proc/sys/net/ipv4/tcp_keepalive_probes
+ * probes to be sent. The value of TCP_KEEPCNT is an integer value between 1 and n,
+ * where n is the value of the systemwide tcp_keepcnt parameter.
+ * ~ >: cat /proc/sys/net/ipv4/tcp_keepalive_probes
* 9
*/
if (setsockopt (sockfd, SOL_TCP, TCP_KEEPCNT, (char *) &opt, sizeof (opt)))
--
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