TheCloud/BindToInterface
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allow source IP binding

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Çağrı 2023-10-15 20:08:13 +00:00 committed by GitHub
parent 785b646713
commit 28b0b08cf8
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1 changed files with 22 additions and 2 deletions
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24
bindToInterface.c
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@ -9,12 +9,23 @@
#include <arpa/inet.h>
#include <stdbool.h>
#include <stdint.h>
#include <unistd.h>
//#define DEBUG
//compile with gcc -nostartfiles -fpic -shared bindToInterface.c -o bindToInterface.so -ldl -D_GNU_SOURCE
//Use with BIND_INTERFACE=<network interface> LD_PRELOAD=./bindInterface.so <your program> like curl ifconfig.me
int bind_to_source_ip(int sockfd, const char *source_ip)
{
struct sockaddr_in source_addr;
memset(&source_addr, 0, sizeof(source_addr));
source_addr.sin_family = AF_INET;
source_addr.sin_addr.s_addr = inet_addr(source_ip);
return bind(sockfd, (struct sockaddr *)&source_addr, sizeof(source_addr));
}
int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen)
{
int *(*original_connect)(int, const struct sockaddr *, socklen_t);
@ -80,6 +91,8 @@ int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen)
{
char *bind_addr_env;
bind_addr_env = getenv("BIND_INTERFACE");
char *source_ip_env;
source_ip_env = getenv("BIND_SOURCE_IP");
struct ifreq interface;
int errorCode;
@ -118,8 +131,15 @@ int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen)
};
}
}
else
{
if(source_ip_env != NULL && strlen(source_ip_env) > 0){
if (bind_to_source_ip(sockfd, source_ip_env) < 0){
perror("bind_to_source_ip failed");
return -1;
}
}
if(!(source_ip_env != NULL && strlen(source_ip_env) > 0) && !(bind_addr_env != NULL && strlen(bind_addr_env) > 0)){
printf("Warning: Programm with LD_PRELOAD startet, but BIND_INTERFACE environment variable not set\n");
fprintf(stderr, "Warning: Programm with LD_PRELOAD startet, but BIND_INTERFACE environment variable not set\n");
}