//获得某个网卡的IP地址
char* GetIpAddress(const char* interfaceName)
{
register int fd, intrface; struct ifreq buf[MAXINTERFACES]; //#define MAXINTERFACES 12 struct ifconf ifc; if ((fd = socket (AF_INET, SOCK_DGRAM, 0)) >= 0) { ifc.ifc_len = sizeof buf; ifc.ifc_buf = (caddr_t) buf; if (!ioctl (fd, SIOCGIFCONF, (char *) &ifc)) { intrface = ifc.ifc_len / sizeof (struct ifreq); while (intrface-- > 0) { if (0 != strcmp(buf[intrface].ifr_name, interfaceName)) continue; //get the ip address of this net device if (!(ioctl (fd, SIOCGIFADDR, (char *) &buf[intrface]))) { ::close(fd); return (inet_ntoa(((struct sockaddr_in*)(&buf[intrface].ifr_addr))->sin_addr)); } else { char str[256]; sprintf (str, "cpm: ioctl device %s", buf[intrface].ifr_name); perror (str); } } } ::close(fd); } return "";
}
bool IsValidIpAddress(const char* ipAddress)
{
struct sockaddr_in sin; sin.sin_family = AF_INET; memset(&sin, 0, sizeof(sin)); if (inet_pton(AF_INET, ipAddress, &sin.sin_addr) <= 0) { return false; } else { char strConvertedIP[MAX_IP_LENGTH]; //#define MAX_IP_LENGTH 30 if (NULL != inet_ntop(AF_INET, &sin.sin_addr, strConvertedIP, MAX_IP_LENGTH) ) { if(0 != strcmp(strConvertedIP, "0.0.0.0")) { return true; } } return false; }
}
bool send_echo_req(int sock_fd,struct sockaddr_in *dstaddr)
{
char buf[100]; size_t len = sizeof(struct icmp); struct icmp *icmp; socklen_t dstlen = sizeof(struct sockaddr_in); bzero(buf, sizeof(buf)); icmp = (struct icmp *)buf; icmp->icmp_type = ICMP_ECHO; icmp->icmp_code = 0; icmp->icmp_id = getpid(); icmp->icmp_seq = 1; icmp->icmp_cksum = in_cksum((uint16_t *) icmp, sizeof(struct icmp)); if (sendto(sockfd, buf, len, 0, (struct sockaddr*)dstaddr, dstlen) == -1) { err_sys("sendto"); return false; } return true; }
bool recv_echo_reply(int sock_fd)
{
char buf[100]; ssize_t n; struct ip *ip; struct icmp *icmp; fd_set rfds; struct timeval tv; int retval; FD_ZERO(&rfds); FD_SET(sockfd, &rfds); tv.tv_sec = 5; tv.tv_usec = 0; retval = select(sockfd+1, &rfds, NULL, NULL, &tv); if (retval == -1) { perror("select()"); return false; } else if (retval) { /* FD_ISSET(0, &rfds) will be true. */ if ((n = read(sockfd, buf, sizeof(buf))) == -1) { err_sys("read"); return false; } ip = (struct ip *)buf; if (ip->ip_p != IPPROTO_ICMP) { fprintf(stderr, "protocol error./r/n"); return false; } icmp = (struct icmp *)(buf + sizeof(struct ip)); if (icmp->icmp_type == ICMP_ECHOREPLY) { if (icmp->icmp_id != getpid()) { fprintf(stderr, "not this process./r/n"); return false; } else { //printf("destination host is alive./r/n"); return true; } } } //printf("ping timeout./n"); return false;
}
uint16_t in_cksum(uint16_t* addr, int len)
{
int nleft = len; uint32_t sum = 0; uint16_t *w = addr; uint16_t answer = 0; while (nleft > 1) { sum += *w++; nleft -= 2; } if (nleft == 1) { *(unsigned char *)(&answer) = *(unsigned char *)w ; sum += answer; } sum = (sum >> 16) + (sum & 0xffff); sum += (sum >> 16); answer = ~sum; return(answer);
}
bool Ping (char* dest)
{
int sockfd; struct sockaddr_in dstaddr; bool ret; char* ipAddr; ipAddr = GetIPAddress(m_wirelessNetworkDevice); if(!IsValidIPAddress(ipAddr.toUtf8().constData())) return false; if ((sockfd = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP)) == -1) //ICMP协议，原始套接字类型 { err_sys("socket"); return false; } bzero(&dstaddr, sizeof(dstaddr)); dstaddr.sin_family = AF_INET; dstaddr.sin_port = htons(0); //printf("dest is %s/n",dest); if (inet_pton(AF_INET, dest, &dstaddr.sin_addr) <= 0) { err_sys("inet_pton"); ::close(sockfd); return false; } ret = send_echo_req(sockfd, &dstaddr); if (!ret) { ::close(sockfd); return false; } ret = recv_echo_reply(sockfd); if (ret) { ::close(sockfd); return true; } else { ::close(sockfd); return false; }
}
以上是Linux下的代码。
