简单的Linux环境下多线程TCP服务程序框架
运行环境：Linux2.6以上
文件说明：tcputil.c --------------- TCP多线程服务框架实现
tcputil.h --------------- 公开函数声明
使用说明：
发送消息必须采用固定的(消息大小，消息体）这种流边界方式，其中消息大小是uint32_t类型，并且是网络字节序。
直接调用start（监听IP, 监听端口，自定义消息处理函数）即可；主要是提供自定义的消息处理函数，原型为：
int msg_handler(int socket, void* buf, uint32_t n)，其中: socket-接收消息的socket，buf-消息体内存，n-消息体长度。
几个关键点：
（1）发送和接收n个字节的方法，在readn()和writen()函数实现；
（2）向派生线程传递参数时，注意并发导致的同步问题，参见start()函数中的传参实现；
（3）遵循“malloc和free要成对存在于同一个函数中”，但是（2）违反了这个原则，是否有更好的解决方案？
（4）采用了回调函数机制（类似C#中的事件）来让库使用着自定义消息处理函数；（这也是为了遵循（3）采取的策略）；
（5）TCP流边界，采取了（消息大小，消息体）的方式，其中消息大小为4字节无符号整数。
存在问题：
（1）性能问题，目前是直接分配与消息体大小同样的内存来接收消息体；
（2）大消息问题，目前消息不能大于int32_t的最大值，对于大数据量传送，请在消息体内实现自定义的用户消息格式来把大数据分块传送；
源码：tcputil.h
#ifndef TCPUTIL_H
#define TCPUTIL_H
#include
#include
#include
#include
#include
#include
#include
#include
ssize_t writen(int fd, void* buf, size_t n);
ssize_t recvn(int fd, void* buf, size_t n);
/*callback function called after received one message, 0-success, -1-error*/
typedef int (*message_handler)(int socket, void * buf, uint32_t size);
int start(uint32_t listenip, uint16_t listenport, message_handler handler);
#endif 源码：tcputil.c
/**************************************************
*
* $description: collection of functions
* $author: smstong
* $date: Tue Apr 16 10:24:22 CST 2013
*
* ************************************************/
#include
#include
#include
#include
#include
#include
#include
#include
/**************************************************
* func: receive n bytes from socket except an error
* params: fd - socket handle
* buf - memory space to write
* n - size of buf
* return: -1 - error;
* >=0 - actually retceived bytes
*************************************************/
ssize_t recvn(int fd, void* buf, size_t n)
{
char* ptr = (char*)buf; // position pointer
size_t left = n; // bytes left to read
while(left > 0) {
size_t nread = read(fd, ptr, left);
if(nread<0) {
if(errno==EINTR) { // an error occured
nread = 0;
} else {
return -1;
}
} else if(nread==0) { //normally disconnect, FIN segment received
break;
} else {
left -= nread;
ptr += nread;
}
}
return (n-left);
}
/********************************************************
* function: write n bytes to socket except error
* params: fd - socket hanle
* buf - src memory
* n - bytes to write
* return: -1 - error
* >=0 - bytes actually written
* ******************************************************/
ssize_t writen(int fd, void* buf, size_t n)
{
char* ptr = (char*)buf;
size_t left = n;
while(left > 0) {
size_t nwrite = write(fd, ptr,left);
if(nwrite<0) {
if(errno==EINTR) {
nwrite = 0;
} else {
return -1;
}
} else if(nwrite==0) {
break;
} else {
left -= nwrite;
ptr += nwrite;
}
}
return (n-left);
}
static void * thread_f(void *); //thread function
typedef int (*message_handler)(int, void *, uint32_t); // callback function called after received one message
/*************************************************************
*
* one thread per connection frameset
*
* ***********************************************************/
// thread function's args
struct thread_arg {
int socket;
message_handler msg_handler;
};
int start(uint32_t listenip, uint16_t listenport, message_handler handler)
{
int listenfd, connfd;
struct sockaddr_in servaddr;
char buff[4096];
int n;
if( (listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ){
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_addr.s_addr = htonl(listenip);
servaddr.sin_port = htons(listenport);
if( bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1){
printf("bind socket error: %s(errno: %d)\n",strerror(errno),errno);
return -1;
}
if( listen(listenfd, 10) == -1){
printf("listen socket error: %s(errno: %d)\n",strerror(errno),errno);
return -1;
}
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;
}
/* create a new thread to handle this connection */
pthread_t tid = 0;
int rc = 0;
struct thread_arg *parg = malloc(sizeof(struct thread_arg));
if(NULL==parg) {
printf("error malloc: %s\n", strerror(errno));
return -1;
}
parg->socket = connfd;
parg->msg_handler = handler;
if(0 != (rc=pthread_create(&tid, NULL, thread_f, parg))) {
printf("%s: %s\n", __func__, strerror(rc));
}
printf(" create thread %u to handle connection %d \n", tid, connfd);
}
close(listenfd);
return 0;
}
/***************************
* fun: receive one message
* params: connfd - socket handle
* return: 0 - success;
* -1 - error
*
* **************************/
static int recv_one_message(int connfd, message_handler post_recv_one)
{
uint32_t msg_len = 0; /* message length */
/* recv length */
if(4 != recvn(connfd, &msg_len, 4)) { // something wrong
return -1;
}
msg_len = ntohl(msg_len);
/* recv body */
if(msg_len > 0x7FFFFFFF) {
printf("message body to large\n");
return -1;
}
char* buf = malloc(msg_len);/* allocate memory for message body*/
if(NULL == buf) {
printf("%s: malloc failed!\n", __func__);
return -1;
}
if(msg_len != recvn(connfd, buf, msg_len)) {
free(buf);
return -1;
}
if(0!=post_recv_one(connfd, buf, msg_len)) { // callback
free(buf);
return -1;
}
free(buf);
return 0;
}
/* thread to handle a connection */
static void * thread_f(void * arg)
{
printf(" enter thread %u\n", pthread_self());
struct thread_arg targ = *((struct thread_arg*)arg);
int connfd = targ.socket;
message_handler post_recv_one = targ.msg_handler;
free(arg);
int i = 0;
while(1) {
if(0 != recv_one_message(connfd, post_recv_one)) {
break;
}
printf("message : %d\n", i++);
}
close(connfd);
printf(" leave thread %u\n", pthread_self());
}
源码：测试例子 server.c，接收消息写入文件data中。
#include "tcputil.h"
#include
/* callback called after one message received. */
int msg_handler(int fd, void* buf, uint32_t n)
{
char* msg = (char*)buf;
FILE* fp = fopen("data", "w");
if(NULL == fp) {
printf("%s\n", strerror(errno));
fclose(fp);
return -1;
}
if(n != fwrite(msg, 1, n, fp)) {
printf("write error:\n");
fclose(fp);
return -1;
}
fclose(fp);
return 0;
}
int main(int argc, char** argv)
{
start(0,6666, msg_handler);
}
using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
SendTcpMsg(File.ReadAllBytes(@"F:\核心软件备份\TomatoWin2k3.SP2.R2.iso"));
}
static void SendTcpMsg(Byte[] msgBody)
{
Socket sock = null;
try
{
sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
sock.Connect("172.16.35.135", 6666);
byte[] msgHead = BitConverter.GetBytes(IPAddress.HostToNetworkOrder(msgBody.Length));
sock.Send(msgHead);
sock.Send(msgBody);
}
catch (Exception ex)
{
Console.Write(ex.Message);
}
finally
{
if(sock!=null)
sock.Close();
}
}
}
}