Socket局域网聊天模拟

// // IPAdress.c // WhatsMyIP // // Created by 发兵 杨 on 12-6-7. // Copyright (c) 2012年 __MyCompanyName__. All rights reserved. // #include <stdio.h> /* As far as I know there is only one hacky way to do that. You basically open a socket and get its address using POSIX functions. Here is the code I used for this: */ /* * IPAdress.h * * */ #define MAXADDRS 32 extern char *if_names[MAXADDRS]; extern char *ip_names[MAXADDRS]; extern char *hw_addrs[MAXADDRS]; extern unsigned long ip_addrs[MAXADDRS]; // Function prototypes void InitAddresses(); void FreeAddresses(); void GetIPAddresses(); void GetHWAddresses(); /* * IPAddress.c * */ //#include "IPAddress.h" #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/ioctl.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netdb.h> #include <arpa/inet.h> #include <sys/sockio.h> #include <net/if.h> #include <errno.h> #include <net/if_dl.h> #define min(a,b) ((a) < (b) ? (a) : (b)) #define max(a,b) ((a) > (b) ? (a) : (b)) #define BUFFERSIZE 4000 char *if_names[MAXADDRS]; char *ip_names[MAXADDRS]; char *hw_addrs[MAXADDRS]; unsigned long ip_addrs[MAXADDRS]; static int nextAddr = 0; void InitAddresses() { int i; for (i=0; i<MAXADDRS; ++i) { if_names[i] = ip_names[i] = hw_addrs[i] = NULL; ip_addrs[i] = 0; } } void FreeAddresses() { int i; for (i=0; i<MAXADDRS; ++i) { if (if_names[i] != 0) free(if_names[i]); if (ip_names[i] != 0) free(ip_names[i]); if (hw_addrs[i] != 0) free(hw_addrs[i]); ip_addrs[i] = 0; } InitAddresses(); } void GetIPAddresses() { int i, len, flags; char buffer[BUFFERSIZE], *ptr, lastname[IFNAMSIZ], *cptr; struct ifconf ifc; struct ifreq *ifr, ifrcopy; struct sockaddr_in *sin; char temp[80]; int sockfd; for (i=0; i<MAXADDRS; ++i) { if_names[i] = ip_names[i] = NULL; ip_addrs[i] = 0; } sockfd = socket(AF_INET, SOCK_DGRAM, 0); if (sockfd < 0) { perror("socket failed"); return; } ifc.ifc_len = BUFFERSIZE; ifc.ifc_buf = buffer; if (ioctl(sockfd, SIOCGIFCONF, &ifc) < 0) { perror("ioctl error"); return; } lastname[0] = 0; for (ptr = buffer; ptr < buffer + ifc.ifc_len; ) { ifr = (struct ifreq *)ptr; len = max(sizeof(struct sockaddr), ifr->ifr_addr.sa_len); ptr += sizeof(ifr->ifr_name) + len; // for next one in buffer if (ifr->ifr_addr.sa_family != AF_INET) { continue; // ignore if not desired address family } if ((cptr = (char *)strchr(ifr->ifr_name, ':')) != NULL) { *cptr = 0; // replace colon will null } if (strncmp(lastname, ifr->ifr_name, IFNAMSIZ) == 0) { continue; /* already processed this interface */ } memcpy(lastname, ifr->ifr_name, IFNAMSIZ); ifrcopy = *ifr; ioctl(sockfd, SIOCGIFFLAGS, &ifrcopy); flags = ifrcopy.ifr_flags; if ((flags & IFF_UP) == 0) { continue; // ignore if interface not up } if_names[nextAddr] = (char *)malloc(strlen(ifr->ifr_name)+1); if (if_names[nextAddr] == NULL) { return; } strcpy(if_names[nextAddr], ifr->ifr_name); sin = (struct sockaddr_in *)&ifr->ifr_addr; strcpy(temp, inet_ntoa(sin->sin_addr)); ip_names[nextAddr] = (char *)malloc(strlen(temp)+1); if (ip_names[nextAddr] == NULL) { return; } strcpy(ip_names[nextAddr], temp); ip_addrs[nextAddr] = sin->sin_addr.s_addr; ++nextAddr; } close(sockfd); } void GetHWAddresses() { struct ifconf ifc; struct ifreq *ifr; int i, sockfd; char buffer[BUFFERSIZE], *cp, *cplim; char temp[80]; for (i=0; i<MAXADDRS; ++i) { hw_addrs[i] = NULL; } sockfd = socket(AF_INET, SOCK_DGRAM, 0); if (sockfd < 0) { perror("socket failed"); return; } ifc.ifc_len = BUFFERSIZE; ifc.ifc_buf = buffer; if (ioctl(sockfd, SIOCGIFCONF, (char *)&ifc) < 0) { perror("ioctl error"); close(sockfd); return; } ifr = ifc.ifc_req; cplim = buffer + ifc.ifc_len; for (cp=buffer; cp < cplim; ) { ifr = (struct ifreq *)cp; if (ifr->ifr_addr.sa_family == AF_LINK) { struct sockaddr_dl *sdl = (struct sockaddr_dl *)&ifr->ifr_addr; int a,b,c,d,e,f; int i; strcpy(temp, (char *)ether_ntoa(LLADDR(sdl))); sscanf(temp, "%x:%x:%x:%x:%x:%x", &a, &b, &c, &d, &e, &f); sprintf(temp, "%02X:%02X:%02X:%02X:%02X:%02X",a,b,c,d,e,f); for (i=0; i<MAXADDRS; ++i) { if ((if_names[i] != NULL) && (strcmp(ifr->ifr_name,if_names[i]) == 0)) { if (hw_addrs[i] == NULL) { hw_addrs[i] = (char *)malloc(strlen(temp)+1); strcpy(hw_addrs[i], temp); break; } } } } cp += sizeof(ifr->ifr_name) + max(sizeof(ifr->ifr_addr), ifr->ifr_addr.sa_len); } close(sockfd); }