Browse Source
- New lib/getmyip.c/h with get_outgoing_ip(), get_default_local_ip(), get_local_ip_by_index() - Uses UDP connect + getsockname instead of /proc/net/route parsing - Supports both IPv4 and IPv6 - Updated etcp_socket_add() to use new functions for interface_addr detectioncongestion
Evgeny
5 months ago
4 changed files with 295 additions and 13 deletions
@ -0,0 +1,204 @@
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/**
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* getmyip.c - Get local IP for outgoing connections |
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* Определяет локальный IP адрес, который будет использоваться |
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* при отправке пакетов на заданный destination. |
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*/ |
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#include "getmyip.h" |
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#include "platform_compat.h" |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#ifdef _WIN32 |
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# include <winsock2.h> |
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# include <ws2tcpip.h> |
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# pragma comment(lib, "ws2_32.lib") |
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typedef SOCKET socket_t; |
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# define SOCKET_INVALID INVALID_SOCKET |
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#else |
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# include <unistd.h> |
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# include <ifaddrs.h> |
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# include <net/if.h> |
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typedef int socket_t; |
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# define SOCKET_INVALID (-1) |
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#endif |
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static void socket_close(socket_t s) |
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{ |
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#ifdef _WIN32 |
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if (s != SOCKET_INVALID) |
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closesocket(s); |
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#else |
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if (s >= 0) |
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close(s); |
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#endif |
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} |
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static int net_init(void) |
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{ |
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#ifdef _WIN32 |
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static int done = 0; |
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if (!done) { |
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WSADATA wsa; |
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if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0) |
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return -1; |
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done = 1; |
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} |
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#endif |
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return 0; |
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} |
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int get_outgoing_ip(const char* dst_ip, int dst_port, int family, |
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const struct sockaddr_storage* local_ip, |
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struct sockaddr_storage* result) |
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{ |
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socket_t sock = SOCKET_INVALID; |
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int ret = -1; |
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struct sockaddr_storage src; |
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socklen_t src_len = sizeof(src); |
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if (!dst_ip || !result) |
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return -1; |
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memset(result, 0, sizeof(*result)); |
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memset(&src, 0, sizeof(src)); |
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if (net_init() != 0) |
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return -1; |
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if (family != AF_INET && family != AF_INET6) |
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return -1; |
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// Create UDP socket
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sock = socket(family, SOCK_DGRAM, IPPROTO_UDP); |
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if (sock == SOCKET_INVALID) |
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return -1; |
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// Bind to local address if specified
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if (local_ip && local_ip->ss_family != 0) { |
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socklen_t local_len = (family == AF_INET) ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6); |
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if (bind(sock, (struct sockaddr*)local_ip, local_len) != 0) { |
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socket_close(sock); |
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return -1; |
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} |
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} else { |
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// Bind to INADDR_ANY
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struct sockaddr_in any4; |
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struct sockaddr_in6 any6; |
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if (family == AF_INET) { |
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memset(&any4, 0, sizeof(any4)); |
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any4.sin_family = AF_INET; |
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any4.sin_addr.s_addr = INADDR_ANY; |
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any4.sin_port = 0; |
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if (bind(sock, (struct sockaddr*)&any4, sizeof(any4)) != 0) { |
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socket_close(sock); |
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return -1; |
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} |
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} else { |
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memset(&any6, 0, sizeof(any6)); |
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any6.sin6_family = AF_INET6; |
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any6.sin6_addr = in6addr_any; |
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any6.sin6_port = 0; |
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if (bind(sock, (struct sockaddr*)&any6, sizeof(any6)) != 0) { |
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socket_close(sock); |
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return -1; |
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} |
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} |
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} |
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// Connect to destination (kernel calculates route)
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if (family == AF_INET) { |
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struct sockaddr_in dst; |
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memset(&dst, 0, sizeof(dst)); |
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dst.sin_family = AF_INET; |
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dst.sin_port = htons((uint16_t)dst_port); |
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if (inet_pton(AF_INET, dst_ip, &dst.sin_addr) != 1) |
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goto end; |
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if (connect(sock, (struct sockaddr*)&dst, sizeof(dst)) != 0) |
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goto end; |
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} else { |
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struct sockaddr_in6 dst; |
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memset(&dst, 0, sizeof(dst)); |
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dst.sin6_family = AF_INET6; |
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dst.sin6_port = htons((uint16_t)dst_port); |
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if (inet_pton(AF_INET6, dst_ip, &dst.sin6_addr) != 1) |
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goto end; |
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if (connect(sock, (struct sockaddr*)&dst, sizeof(dst)) != 0) |
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goto end; |
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} |
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// Get local address
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if (getsockname(sock, (struct sockaddr*)&src, &src_len) != 0) |
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goto end; |
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// Copy result (only IP, port = 0)
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memcpy(result, &src, sizeof(src)); |
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if (family == AF_INET) { |
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((struct sockaddr_in*)result)->sin_port = 0; |
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} else { |
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((struct sockaddr_in6*)result)->sin6_port = 0; |
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} |
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ret = 0; |
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end: |
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socket_close(sock); |
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return ret; |
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} |
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int get_default_local_ip(int family, struct sockaddr_storage* result) |
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{ |
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if (family == AF_INET) { |
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return get_outgoing_ip("8.8.8.8", 53, family, NULL, result); |
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} else if (family == AF_INET6) { |
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return get_outgoing_ip("2001:4860:4860::8888", 53, family, NULL, result); |
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} |
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return -1; |
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} |
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#ifndef _WIN32 |
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int get_local_ip_by_index(uint32_t ifindex, struct sockaddr_storage* result) |
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{ |
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struct ifaddrs *ifaddr, *ifa; |
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int ret = -1; |
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if (!result) |
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return -1; |
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memset(result, 0, sizeof(*result)); |
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if (getifaddrs(&ifaddr) == -1) |
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return -1; |
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for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) { |
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if (ifa->ifa_addr == NULL) |
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continue; |
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if (ifa->ifa_name == NULL) |
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continue; |
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unsigned int idx = if_nametoindex(ifa->ifa_name); |
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if (idx != ifindex) |
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continue; |
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if (ifa->ifa_addr->sa_family != AF_INET) |
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continue; |
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struct sockaddr_in *addr = (struct sockaddr_in *)ifa->ifa_addr; |
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struct sockaddr_in *res = (struct sockaddr_in*)result; |
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res->sin_family = AF_INET; |
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res->sin_addr.s_addr = addr->sin_addr.s_addr; |
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res->sin_port = 0; |
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ret = 0; |
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break; |
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} |
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freeifaddrs(ifaddr); |
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return ret; |
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} |
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#else |
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int get_local_ip_by_index(uint32_t ifindex, struct sockaddr_storage* result) |
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{ |
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(void)ifindex; |
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(void)result; |
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return -1; |
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} |
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#endif |
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@ -0,0 +1,65 @@
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/**
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* getmyip.h - Get local IP for outgoing connections |
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* Определяет локальный IP адрес, который будет использоваться |
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* при отправке пакетов на заданный destination. |
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*/ |
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#ifndef GETMYIP_H |
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#define GETMYIP_H |
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#include <stdint.h> |
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#include <sys/types.h> |
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#include <sys/socket.h> |
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#include <netinet/in.h> |
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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/**
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* Get local IPv4 or IPv6 address for outgoing connection |
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* |
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* @param dst_ip - Target IP (e.g., "8.8.8.8" or "2001:4860:4860::8888") |
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* @param dst_port - Target port (any open port, e.g., 53) |
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* @param family - AF_INET or AF_INET6 |
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* @param local_ip - If not NULL and ss_family != 0, bind to this local address first |
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* @param result - Output: local IP address (port will be 0) |
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* |
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* Returns 0 on success, -1 on error |
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* |
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* Algorithm: |
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* 1. Create UDP socket |
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* 2. If local_ip specified, bind to it (for binding to specific interface) |
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* 3. Connect to dst_ip:dst_port (kernel calculates route, no packets sent) |
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* 4. Use getsockname() to get actual local IP |
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* 5. Return result (only IP, port = 0) |
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*/ |
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int get_outgoing_ip(const char* dst_ip, int dst_port, int family, |
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const struct sockaddr_storage* local_ip, |
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struct sockaddr_storage* result); |
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/**
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* Simplified version - get local IP for any destination (default route) |
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* |
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* @param family - AF_INET or AF_INET6 |
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* @param result - Output: local IP address |
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* |
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* Returns 0 on success, -1 on error |
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*/ |
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int get_default_local_ip(int family, struct sockaddr_storage* result); |
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/**
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* Get local IPv4 address by interface index |
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* |
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* @param ifindex - Interface index (from if_nametoindex) |
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* @param result - Output: local IPv4 address |
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* |
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* Returns 0 on success, -1 on error |
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*/ |
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int get_local_ip_by_index(uint32_t ifindex, struct sockaddr_storage* result); |
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#ifdef __cplusplus |
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} |
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#endif |
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#endif /* GETMYIP_H */ |
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