diff --git a/README.md b/README.md index 9f506bc..196437c 100644 --- a/README.md +++ b/README.md @@ -1,4 +1,4 @@ android-ifaddrs =============== -An implementation of getifaddrs() for Android. +An implementation of getifaddrs() for Android, since the NDK does not natively support it. Works just like you would expect on regular Linux. License information is present in each file. diff --git a/ifaddrs.c b/ifaddrs.c new file mode 100644 index 0000000..338fff8 --- /dev/null +++ b/ifaddrs.c @@ -0,0 +1,600 @@ +/* +Copyright (c) 2013, Kenneth MacKay +All rights reserved. + +Redistribution and use in source and binary forms, with or without modification, +are permitted provided that the following conditions are met: + * Redistributions of source code must retain the above copyright notice, this + list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright notice, + this list of conditions and the following disclaimer in the documentation + and/or other materials provided with the distribution. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND +ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR +ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON +ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + +#include "ifaddrs.h" + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +typedef struct NetlinkList +{ + struct NetlinkList *m_next; + struct nlmsghdr *m_data; + unsigned int m_size; +} NetlinkList; + +static int netlink_socket(void) +{ + int l_socket = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE); + if(l_socket < 0) + { + return -1; + } + + struct sockaddr_nl l_addr; + memset(&l_addr, 0, sizeof(l_addr)); + l_addr.nl_family = AF_NETLINK; + if(bind(l_socket, (struct sockaddr *)&l_addr, sizeof(l_addr)) < 0) + { + close(l_socket); + return -1; + } + + return l_socket; +} + +static int netlink_send(int p_socket, int p_request) +{ + char l_buffer[NLMSG_ALIGN(sizeof(struct nlmsghdr)) + NLMSG_ALIGN(sizeof(struct rtgenmsg))]; + memset(l_buffer, 0, sizeof(l_buffer)); + struct nlmsghdr *l_hdr = (struct nlmsghdr *)l_buffer; + struct rtgenmsg *l_msg = (struct rtgenmsg *)NLMSG_DATA(l_hdr); + + l_hdr->nlmsg_len = NLMSG_LENGTH(sizeof(*l_msg)); + l_hdr->nlmsg_type = p_request; + l_hdr->nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST; + l_hdr->nlmsg_pid = 0; + l_hdr->nlmsg_seq = p_socket; + l_msg->rtgen_family = AF_UNSPEC; + + struct sockaddr_nl l_addr; + memset(&l_addr, 0, sizeof(l_addr)); + l_addr.nl_family = AF_NETLINK; + return (sendto(p_socket, l_hdr, l_hdr->nlmsg_len, 0, (struct sockaddr *)&l_addr, sizeof(l_addr))); +} + +static int netlink_recv(int p_socket, void *p_buffer, size_t p_len) +{ + struct msghdr l_msg; + struct iovec l_iov = { p_buffer, p_len }; + struct sockaddr_nl l_addr; + int l_result; + + for(;;) + { + l_msg.msg_name = (void *)&l_addr; + l_msg.msg_namelen = sizeof(l_addr); + l_msg.msg_iov = &l_iov; + l_msg.msg_iovlen = 1; + l_msg.msg_control = NULL; + l_msg.msg_controllen = 0; + l_msg.msg_flags = 0; + int l_result = recvmsg(p_socket, &l_msg, 0); + + if(l_result < 0) + { + if(errno == EINTR) + { + continue; + } + return -2; + } + + if(l_msg.msg_flags & MSG_TRUNC) + { // buffer was too small + return -1; + } + return l_result; + } +} + +static struct nlmsghdr *getNetlinkResponse(int p_socket, int *p_size, int *p_done) +{ + size_t l_size = 4096; + void *l_buffer = NULL; + + for(;;) + { + free(l_buffer); + l_buffer = malloc(l_size); + + int l_read = netlink_recv(p_socket, l_buffer, l_size); + *p_size = l_read; + if(l_read == -2) + { + free(l_buffer); + return NULL; + } + if(l_read >= 0) + { + pid_t l_pid = getpid(); + struct nlmsghdr *l_hdr; + for(l_hdr = (struct nlmsghdr *)l_buffer; NLMSG_OK(l_hdr, (unsigned int)l_read); l_hdr = (struct nlmsghdr *)NLMSG_NEXT(l_hdr, l_read)) + { + if((pid_t)l_hdr->nlmsg_pid != l_pid || (int)l_hdr->nlmsg_seq != p_socket) + { + continue; + } + + if(l_hdr->nlmsg_type == NLMSG_DONE) + { + *p_done = 1; + break; + } + + if(l_hdr->nlmsg_type == NLMSG_ERROR) + { + free(l_buffer); + return NULL; + } + } + return l_buffer; + } + + l_size *= 2; + } +} + +static NetlinkList *newListItem(struct nlmsghdr *p_data, unsigned int p_size) +{ + NetlinkList *l_item = malloc(sizeof(NetlinkList)); + l_item->m_next = NULL; + l_item->m_data = p_data; + l_item->m_size = p_size; + return l_item; +} + +static void freeResultList(NetlinkList *p_list) +{ + NetlinkList *l_cur; + while(p_list) + { + l_cur = p_list; + p_list = p_list->m_next; + free(l_cur->m_data); + free(l_cur); + } +} + +static NetlinkList *getResultList(int p_socket, int p_request) +{ + if(netlink_send(p_socket, p_request) < 0) + { + return NULL; + } + + NetlinkList *l_list = NULL; + NetlinkList *l_end = NULL; + int l_size; + int l_done = 0; + while(!l_done) + { + struct nlmsghdr *l_hdr = getNetlinkResponse(p_socket, &l_size, &l_done); + if(!l_hdr) + { // error + freeResultList(l_list); + return NULL; + } + + NetlinkList *l_item = newListItem(l_hdr, l_size); + if(!l_list) + { + l_list = l_item; + } + else + { + l_end->m_next = l_item; + } + l_end = l_item; + } + return l_list; +} + +static size_t maxSize(size_t a, size_t b) +{ + return (a > b ? a : b); +} + +static size_t calcAddrLen(sa_family_t p_family, int p_dataSize) +{ + switch(p_family) + { + case AF_INET: + return sizeof(struct sockaddr_in); + case AF_INET6: + return sizeof(struct sockaddr_in6); + case AF_PACKET: + return maxSize(sizeof(struct sockaddr_ll), offsetof(struct sockaddr_ll, sll_addr) + p_dataSize); + default: + return maxSize(sizeof(struct sockaddr), offsetof(struct sockaddr, sa_data) + p_dataSize); + } +} + +static void makeSockaddr(sa_family_t p_family, struct sockaddr *p_dest, void *p_data, size_t p_size) +{ + switch(p_family) + { + case AF_INET: + memcpy(&((struct sockaddr_in*)p_dest)->sin_addr, p_data, p_size); + break; + case AF_INET6: + memcpy(&((struct sockaddr_in6*)p_dest)->sin6_addr, p_data, p_size); + break; + case AF_PACKET: + memcpy(((struct sockaddr_ll*)p_dest)->sll_addr, p_data, p_size); + ((struct sockaddr_ll*)p_dest)->sll_halen = p_size; + break; + default: + memcpy(p_dest->sa_data, p_data, p_size); + break; + } + p_dest->sa_family = p_family; +} + +static void addToEnd(struct ifaddrs **p_resultList, struct ifaddrs *p_entry) +{ + if(!*p_resultList) + { + *p_resultList = p_entry; + } + else + { + struct ifaddrs *l_cur = *p_resultList; + while(l_cur->ifa_next) + { + l_cur = l_cur->ifa_next; + } + l_cur->ifa_next = p_entry; + } +} + +static void interpretLink(struct nlmsghdr *p_hdr, struct ifaddrs **p_links, struct ifaddrs **p_resultList) +{ + struct ifinfomsg *l_info = (struct ifinfomsg *)NLMSG_DATA(p_hdr); + + size_t l_nameSize = 0; + size_t l_addrSize = 0; + size_t l_dataSize = 0; + + size_t l_rtaSize = NLMSG_PAYLOAD(p_hdr, sizeof(struct ifinfomsg)); + struct rtattr *l_rta; + for(l_rta = (struct rtattr *)(((char *)l_info) + NLMSG_ALIGN(sizeof(struct ifinfomsg))); RTA_OK(l_rta, l_rtaSize); l_rta = RTA_NEXT(l_rta, l_rtaSize)) + { + void *l_rtaData = RTA_DATA(l_rta); + size_t l_rtaDataSize = RTA_PAYLOAD(l_rta); + switch(l_rta->rta_type) + { + case IFLA_ADDRESS: + case IFLA_BROADCAST: + l_addrSize += NLMSG_ALIGN(calcAddrLen(AF_PACKET, l_rtaDataSize)); + break; + case IFLA_IFNAME: + l_nameSize += NLMSG_ALIGN(l_rtaSize + 1); + break; + case IFLA_STATS: + l_dataSize += NLMSG_ALIGN(l_rtaSize); + break; + default: + break; + } + } + + struct ifaddrs *l_entry = malloc(sizeof(struct ifaddrs) + l_nameSize + l_addrSize + l_dataSize); + memset(l_entry, 0, sizeof(struct ifaddrs)); + l_entry->ifa_name = ""; + + char *l_name = ((char *)l_entry) + sizeof(struct ifaddrs); + char *l_addr = l_name + l_nameSize; + char *l_data = l_addr + l_addrSize; + + l_entry->ifa_flags = l_info->ifi_flags; + + l_rtaSize = NLMSG_PAYLOAD(p_hdr, sizeof(struct ifinfomsg)); + for(l_rta = (struct rtattr *)(((char *)l_info) + NLMSG_ALIGN(sizeof(struct ifinfomsg))); RTA_OK(l_rta, l_rtaSize); l_rta = RTA_NEXT(l_rta, l_rtaSize)) + { + void *l_rtaData = RTA_DATA(l_rta); + size_t l_rtaDataSize = RTA_PAYLOAD(l_rta); + switch(l_rta->rta_type) + { + case IFLA_ADDRESS: + case IFLA_BROADCAST: + { + size_t l_addrLen = calcAddrLen(AF_PACKET, l_rtaDataSize); + makeSockaddr(AF_PACKET, (struct sockaddr *)l_addr, l_rtaData, l_rtaDataSize); + ((struct sockaddr_ll *)l_addr)->sll_ifindex = l_info->ifi_index; + ((struct sockaddr_ll *)l_addr)->sll_hatype = l_info->ifi_type; + if(l_rta->rta_type == IFLA_ADDRESS) + { + l_entry->ifa_addr = (struct sockaddr *)l_addr; + } + else + { + l_entry->ifa_broadaddr = (struct sockaddr *)l_addr; + } + l_addr += NLMSG_ALIGN(l_addrLen); + break; + } + case IFLA_IFNAME: + strncpy(l_name, l_rtaData, l_rtaDataSize); + l_name[l_rtaDataSize] = '\0'; + l_entry->ifa_name = l_name; + break; + case IFLA_STATS: + memcpy(l_data, l_rtaData, l_rtaDataSize); + l_entry->ifa_data = l_data; + break; + default: + break; + } + } + + addToEnd(p_resultList, l_entry); + p_links[l_info->ifi_index - 1] = l_entry; +} + +static void interpretAddr(struct nlmsghdr *p_hdr, struct ifaddrs **p_links, struct ifaddrs **p_resultList) +{ + struct ifaddrmsg *l_info = (struct ifaddrmsg *)NLMSG_DATA(p_hdr); + + size_t l_nameSize = 0; + size_t l_addrSize = 0; + + int l_addedNetmask = 0; + + size_t l_rtaSize = NLMSG_PAYLOAD(p_hdr, sizeof(struct ifaddrmsg)); + struct rtattr *l_rta; + for(l_rta = (struct rtattr *)(((char *)l_info) + NLMSG_ALIGN(sizeof(struct ifaddrmsg))); RTA_OK(l_rta, l_rtaSize); l_rta = RTA_NEXT(l_rta, l_rtaSize)) + { + void *l_rtaData = RTA_DATA(l_rta); + size_t l_rtaDataSize = RTA_PAYLOAD(l_rta); + if(l_info->ifa_family == AF_PACKET) + { + continue; + } + + switch(l_rta->rta_type) + { + case IFA_ADDRESS: + case IFA_LOCAL: + if((l_info->ifa_family == AF_INET || l_info->ifa_family == AF_INET6) && !l_addedNetmask) + { // make room for netmask + l_addrSize += NLMSG_ALIGN(calcAddrLen(l_info->ifa_family, l_rtaDataSize)); + l_addedNetmask = 1; + } + case IFA_BROADCAST: + l_addrSize += NLMSG_ALIGN(calcAddrLen(l_info->ifa_family, l_rtaDataSize)); + break; + case IFA_LABEL: + l_nameSize += NLMSG_ALIGN(l_rtaSize + 1); + break; + default: + break; + } + } + + struct ifaddrs *l_entry = malloc(sizeof(struct ifaddrs) + l_nameSize + l_addrSize); + memset(l_entry, 0, sizeof(struct ifaddrs)); + l_entry->ifa_name = p_links[l_info->ifa_index - 1]->ifa_name; + + char *l_name = ((char *)l_entry) + sizeof(struct ifaddrs); + char *l_addr = l_name + l_nameSize; + + l_entry->ifa_flags = l_info->ifa_flags | p_links[l_info->ifa_index - 1]->ifa_flags; + + l_rtaSize = NLMSG_PAYLOAD(p_hdr, sizeof(struct ifaddrmsg)); + for(l_rta = (struct rtattr *)(((char *)l_info) + NLMSG_ALIGN(sizeof(struct ifaddrmsg))); RTA_OK(l_rta, l_rtaSize); l_rta = RTA_NEXT(l_rta, l_rtaSize)) + { + void *l_rtaData = RTA_DATA(l_rta); + size_t l_rtaDataSize = RTA_PAYLOAD(l_rta); + switch(l_rta->rta_type) + { + case IFA_ADDRESS: + case IFA_BROADCAST: + case IFA_LOCAL: + { + size_t l_addrLen = calcAddrLen(l_info->ifa_family, l_rtaDataSize); + makeSockaddr(l_info->ifa_family, (struct sockaddr *)l_addr, l_rtaData, l_rtaDataSize); + if(l_info->ifa_family == AF_INET6) + { + if(IN6_IS_ADDR_LINKLOCAL((struct in6_addr *)l_rtaData) || IN6_IS_ADDR_MC_LINKLOCAL((struct in6_addr *)l_rtaData)) + { + ((struct sockaddr_in6 *)l_addr)->sin6_scope_id = l_info->ifa_index; + } + } + + if(l_rta->rta_type == IFA_ADDRESS) + { // apparently in a point-to-point network IFA_ADDRESS contains the dest address and IFA_LOCAL contains the local address + if(l_entry->ifa_addr) + { + l_entry->ifa_dstaddr = (struct sockaddr *)l_addr; + } + else + { + l_entry->ifa_addr = (struct sockaddr *)l_addr; + } + } + else if(l_rta->rta_type == IFA_LOCAL) + { + if(l_entry->ifa_addr) + { + l_entry->ifa_dstaddr = l_entry->ifa_addr; + } + l_entry->ifa_addr = (struct sockaddr *)l_addr; + } + else + { + l_entry->ifa_broadaddr = (struct sockaddr *)l_addr; + } + l_addr += NLMSG_ALIGN(l_addrLen); + break; + } + case IFA_LABEL: + strncpy(l_name, l_rtaData, l_rtaDataSize); + l_name[l_rtaDataSize] = '\0'; + l_entry->ifa_name = l_name; + break; + default: + break; + } + } + + if(l_entry->ifa_addr && (l_entry->ifa_addr->sa_family == AF_INET || l_entry->ifa_addr->sa_family == AF_INET6)) + { + unsigned l_maxPrefix = (l_entry->ifa_addr->sa_family == AF_INET ? 32 : 128); + unsigned l_prefix = (l_info->ifa_prefixlen > l_maxPrefix ? l_maxPrefix : l_info->ifa_prefixlen); + char l_mask[16] = {0}; + unsigned i; + for(i=0; i<(l_prefix/8); ++i) + { + l_mask[i] = 0xff; + } + l_mask[i] = 0xff << (8 - (l_prefix % 8)); + + makeSockaddr(l_entry->ifa_addr->sa_family, (struct sockaddr *)l_addr, l_mask, l_maxPrefix / 8); + l_entry->ifa_netmask = (struct sockaddr *)l_addr; + } + + addToEnd(p_resultList, l_entry); +} + +static void interpret(int p_socket, NetlinkList *p_netlinkList, struct ifaddrs **p_links, struct ifaddrs **p_resultList) +{ + pid_t l_pid = getpid(); + for(; p_netlinkList; p_netlinkList = p_netlinkList->m_next) + { + unsigned int l_nlsize = p_netlinkList->m_size; + struct nlmsghdr *l_hdr; + for(l_hdr = p_netlinkList->m_data; NLMSG_OK(l_hdr, l_nlsize); l_hdr = NLMSG_NEXT(l_hdr, l_nlsize)) + { + if((pid_t)l_hdr->nlmsg_pid != l_pid || (int)l_hdr->nlmsg_seq != p_socket) + { + continue; + } + + if(l_hdr->nlmsg_type == NLMSG_DONE) + { + break; + } + + if(l_hdr->nlmsg_type == RTM_NEWLINK) + { + interpretLink(l_hdr, p_links, p_resultList); + } + else if(l_hdr->nlmsg_type == RTM_NEWADDR) + { + interpretAddr(l_hdr, p_links, p_resultList); + } + } + } +} + +static unsigned countLinks(int p_socket, NetlinkList *p_netlinkList) +{ + unsigned l_links = 0; + pid_t l_pid = getpid(); + for(; p_netlinkList; p_netlinkList = p_netlinkList->m_next) + { + unsigned int l_nlsize = p_netlinkList->m_size; + struct nlmsghdr *l_hdr; + for(l_hdr = p_netlinkList->m_data; NLMSG_OK(l_hdr, l_nlsize); l_hdr = NLMSG_NEXT(l_hdr, l_nlsize)) + { + if((pid_t)l_hdr->nlmsg_pid != l_pid || (int)l_hdr->nlmsg_seq != p_socket) + { + continue; + } + + if(l_hdr->nlmsg_type == NLMSG_DONE) + { + break; + } + + if(l_hdr->nlmsg_type == RTM_NEWLINK) + { + ++l_links; + } + } + } + + return l_links; +} + +int getifaddrs(struct ifaddrs **ifap) +{ + if(!ifap) + { + return -1; + } + *ifap = NULL; + + int l_socket = netlink_socket(); + if(l_socket < 0) + { + return -1; + } + + NetlinkList *l_linkResults = getResultList(l_socket, RTM_GETLINK); + if(!l_linkResults) + { + close(l_socket); + return -1; + } + + NetlinkList *l_addrResults = getResultList(l_socket, RTM_GETADDR); + if(!l_addrResults) + { + close(l_socket); + freeResultList(l_linkResults); + return -1; + } + + unsigned l_numLinks = countLinks(l_socket, l_linkResults) + countLinks(l_socket, l_addrResults); + struct ifaddrs *l_links[l_numLinks]; + memset(l_links, 0, l_numLinks * sizeof(struct ifaddrs *)); + + interpret(l_socket, l_linkResults, l_links, ifap); + interpret(l_socket, l_addrResults, l_links, ifap); + + freeResultList(l_linkResults); + freeResultList(l_addrResults); + close(l_socket); + return 0; +} + +void freeifaddrs(struct ifaddrs *ifa) +{ + struct ifaddrs *l_cur; + while(ifa) + { + l_cur = ifa; + ifa = ifa->ifa_next; + free(l_cur); + } +} diff --git a/ifaddrs.h b/ifaddrs.h new file mode 100644 index 0000000..9cd19fe --- /dev/null +++ b/ifaddrs.h @@ -0,0 +1,54 @@ +/* + * Copyright (c) 1995, 1999 + * Berkeley Software Design, Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * BSDI ifaddrs.h,v 2.5 2000/02/23 14:51:59 dab Exp + */ + +#ifndef _IFADDRS_H_ +#define _IFADDRS_H_ + +struct ifaddrs { + struct ifaddrs *ifa_next; + char *ifa_name; + unsigned int ifa_flags; + struct sockaddr *ifa_addr; + struct sockaddr *ifa_netmask; + struct sockaddr *ifa_dstaddr; + void *ifa_data; +}; + +/* + * This may have been defined in . Note that if is + * to be included it must be included before this header file. + */ +#ifndef ifa_broadaddr +#define ifa_broadaddr ifa_dstaddr /* broadcast address interface */ +#endif + +#include + +__BEGIN_DECLS +extern int getifaddrs(struct ifaddrs **ifap); +extern void freeifaddrs(struct ifaddrs *ifa); +__END_DECLS + +#endif