Shulou(Shulou.com)06/01 Report--

Get all ip of linux kernel (C language)

Get interface ip is often encountered. Record it for later use.

#include #include #include #include #include #include #include #include typedef unsigned int sf_uint32_t;typedef unsigned int in_addr_t;static inline char* print_ip1(sf_uint32_t ip){ unsigned char* ip_tmp = (unsigned char*) &ip; static char buff[20]; memset(buff ,0 ,sizeof(buff)); snprintf(buff, sizeof(buff), "%d.% d.% d.% d", ip_tmp[0], ip_tmp[1], ip_tmp[2], ip_tmp[3]); return buff;}in_addr_tget_myaddr(void){ int sd, i, lastlen = 0; struct ifconf ifc; struct ifreq *ifrp = NULL; in_addr_t addr; char *buf = NULL; if ((sd = socket(AF_INET, SOCK_DGRAM, 0))

< 0) { return 0; } /* * Cope with lots of interfaces and brokenness of ioctl SIOCGIFCONF on * some platforms; see W. R. Stevens, ``Unix Network Programming Volume * I'', p.435. */ for (i = 8;; i += 8) { buf = (char *) calloc(i, sizeof(struct ifreq)); if (buf == NULL) { close(sd); return 0; } ifc.ifc_len = i * sizeof(struct ifreq); ifc.ifc_buf = (caddr_t) buf; if (ioctl(sd, SIOCGIFCONF, (char *) &ifc) < 0) { if (errno != EINVAL || lastlen != 0) { /* * Something has gone genuinely wrong. */ free(buf); close(sd); return 0; } /* * Otherwise, it could just be that the buffer is too small. */ } else { if (ifc.ifc_len == lastlen) { /* * The length is the same as the last time; we're done. */ break; } lastlen = ifc.ifc_len; } free(buf); } for (ifrp = ifc.ifc_req; (char *)ifrp < (char *)ifc.ifc_req + ifc.ifc_len;#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN ifrp = (struct ifreq *)(((char *) ifrp) + sizeof(ifrp->

ifr_name) + ifrp->ifr_addr.sa_len)#else ifrp++#endif ) { if (ifrp->ifr_addr.sa_family != AF_INET) { continue; } addr = ((struct sockaddr_in *) &(ifrp->ifr_addr))->sin_addr.s_addr; if (ioctl(sd, SIOCGIFFLAGS, (char *) ifrp)

< 0) { continue; } if ((ifrp->

ifr_flags & IFF_UP)#ifdef IFF_RUNNING && (ifrp->ifr_flags & IFF_RUNNING)#endif /* IFF_RUNNING */ /*&& ! (ifrp->ifr_flags & IFF_LOOPBACK) && addr != LOOPBACK*/) { /* * I *really* don't understand why this is necessary. Perhaps for * some broken platform? Leave it for now. JBPN */#ifdef SYS_IOCTL_H_HAS_SIOCGIFADDR if (ioctl(sd, SIOCGIFADDR, (char *) ifrp)

< 0) { continue; } addr = ((struct sockaddr_in *) &(ifrp->

ifr_addr))->sin_addr. s_addr;#endif printf("current ip : %s\n",print_ip1(addr)); } } free(buf); close(sd); return 0;}int main(){ get_myaddr();}

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