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force_bind.c
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/*
* Description: Force bind on a specified address
* Author: Catalin(ux) M. BOIE
* E-mail: catab at embedromix dot ro
* Web: http://kernel.embedromix.ro/us/
*/
#define __USE_GNU
#define _GNU_SOURCE
#define __USE_XOPEN2K
#define __USE_LARGEFILE64
#define __USE_FILE_OFFSET64
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <syslog.h>
#include <dlfcn.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <time.h>
#include <errno.h>
#include <dirent.h>
#include <asm/unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <poll.h>
#include "force_bind_config.h"
/* glibc may not be up-to-date at compile time */
#ifndef SO_MARK
#define SO_MARK 36 /* only on some architectures */
#endif
#ifndef SOCK_DCCP
#define SOCK_DCCP 6
#endif
#ifndef IPV6_FLOWINFO_SEND
#define IPV6_FLOWLABEL_MGR 32
#define IPV6_FLOWINFO_SEND 33
#define IPV6_FL_F_CREATE 1
#define IPV6_FL_A_GET 0
#define IPV6_FL_S_ANY 255
#define IPV6_FLOWINFO_MASK 0x0FFFFFFFUL
#define IPV6_FLOWLABEL_MASK 0x000FFFFFUL
struct in6_flowlabel_req {
struct in6_addr flr_dst;
unsigned int flr_label;
unsigned char flr_action;
unsigned char flr_share;
unsigned short flr_flags;
unsigned short flr_expires;
unsigned short flr_linger;
unsigned int __flr_pad;
};
#endif
#define FB_FLAGS_NETSOCK (1 << 0)
#define FB_FLAGS_BIND_CALLED (1 << 1)
#define FB_FLAGS_FLOWINFO_CALLED (1 << 2)
struct private
{
int domain;
int type;
unsigned int flags;
struct sockaddr_storage dest;
socklen_t dest_len;
/* bandwidth */
unsigned long long limit;
unsigned long long rest;
struct timeval last;
};
struct node
{
int fd;
struct private priv;
struct node *next;
};
struct info
{
struct node *head, *tail;
};
static int (*old_bind)(int sockfd, const struct sockaddr *addr, socklen_t addrlen) = NULL;
static int (*old_setsockopt)(int sockfd, int level, int optname, const void *optval, socklen_t optlen);
static int (*old_socket)(int domain, int type, int protocol);
static int (*old_close)(int fd);
static ssize_t (*old_write)(int fd, const void *buf, size_t len);
static ssize_t (*old_send)(int sockfd, const void *buf, size_t len, int flags);
static ssize_t (*old_sendto)(int sockfd, const void *buf, size_t len, int flags, const struct sockaddr *dest_addr, socklen_t addrlen);
static ssize_t (*old_sendmsg)(int sockfd, const struct msghdr *msg, int flags);
static int (*old_accept)(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
static int (*old_accept4)(int sockfd, struct sockaddr *addr, socklen_t *addrlen, int flags);
static int (*old_connect)(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
static int (*old_poll)(struct pollfd *fds, nfds_t nfds, int timeout);
static char *force_address_v4 = NULL;
static char *force_address_v6 = NULL;
static int force_port_v4 = -1;
static int force_port_v6 = -1;
static unsigned int force_tos = 0, tos;
static unsigned int force_ttl = 0, ttl;
static unsigned int force_keepalive = 0, keepalive;
static unsigned int force_mss = 0, mss;
static unsigned int force_reuseaddr = 0, reuseaddr;
static unsigned int force_nodelay = 0, nodelay;
static unsigned long long bw_limit_per_socket = 0;
static unsigned int force_flowinfo = 0, flowinfo;
static unsigned int force_fwmark = 0, fwmark;
static unsigned int force_prio = 0, prio;
static struct private bw_global;
static struct info fdinfo;
static unsigned int verbose = 0;
static char *log_file = NULL;
static FILE *Log = NULL;
static int force_poll_timeout = -1000;
/* Helper functions */
static char *sdomain(const int domain)
{
static char tmp[16];
switch (domain) {
case AF_INET: return "IPv4";
case AF_INET6: return "IPv6";
default: snprintf(tmp, sizeof(tmp), "%d", domain); return tmp;
}
}
static char *stype(const int type)
{
static char tmp[16];
switch (type & 0xfff) {
case SOCK_STREAM: return "stream";
case SOCK_DGRAM: return "dgram";
case SOCK_RAW: return "raw";
case SOCK_SEQPACKET: return "seqpacket";
case SOCK_DCCP: return "dccp";
case SOCK_PACKET: return "packet";
default: snprintf(tmp, sizeof(tmp), "%d", type); return tmp;
}
}
static char *sprotocol(const int protocol)
{
static char tmp[16];
switch (protocol) {
case IPPROTO_TCP: return "tcp";
case IPPROTO_UDP: return "udp";
default: snprintf(tmp, sizeof(tmp), "%d", protocol); return tmp;
}
}
/*
* Fills @out with domain/type/address/port string
*/
static void saddr(char *out, const size_t out_len,
const struct sockaddr_storage *ss)
{
struct sockaddr_in *s4;
struct sockaddr_in6 *s6;
char addr[40], port[8];
switch (ss->ss_family) {
case AF_INET:
s4 = (struct sockaddr_in *) ss;
inet_ntop(AF_INET, (void *) &s4->sin_addr.s_addr, addr, sizeof(struct sockaddr_in));
snprintf(port, sizeof(port), "%d", s4->sin_port);
break;
case AF_INET6:
s6 = (struct sockaddr_in6 *) ss;
inet_ntop(AF_INET6, (void *) &s6->sin6_addr.s6_addr, addr, sizeof(struct sockaddr_in6));
snprintf(port, sizeof(port), "%d", s6->sin6_port);
break;
default:
strcpy(addr, "?");
strcpy(port, "?");
break;
}
snprintf(out, out_len, "%s/%s/%s",
sdomain(ss->ss_family), addr, port);
}
static void xlog(const unsigned int level, const char *format, ...)
{
va_list ap;
if (Log == NULL)
return;
if (level > verbose)
return;
va_start(ap, format);
vfprintf(Log, format, ap);
va_end(ap);
}
static void dump(const unsigned int level, const char *title, const void *buf,
const unsigned int len)
{
unsigned int i;
unsigned char *buf2 = (unsigned char *) buf;
char out[1024];
for (i = 0; i < len; i++)
snprintf(out + i * 3, 4, " %02x", buf2[i]);
xlog(level, "force_bind: dump %s:%s\n", title, out);
}
static struct node *get(const int fd)
{
struct node *p;
p = fdinfo.head;
while (p != NULL) {
if (p->fd == fd)
return p;
p = p->next;
}
return NULL;
}
/*
* List all sockets
*/
static void list(const unsigned int level)
{
struct node *q;
struct private *p;
char dest[128];
xlog(level, "force_bind: list...\n");
q = fdinfo.head;
while (q != NULL) {
if (q->fd == -1) {
q = q->next;
continue;
}
p = &q->priv;
saddr(dest, sizeof(dest), &p->dest);
xlog(level, "\tfd=%4d type=%s flags=%04x limit=%llu"
" rest=%llu last=%u.%06u dest=%s\n",
q->fd, stype(p->type), p->flags, p->limit,
p->rest, p->last.tv_sec, p->last.tv_usec, dest);
q = q->next;
}
}
static void add(const int fd, const struct private *p)
{
struct node *q;
xlog(2, "force_bind: add(fd=%d, ...)\n", fd);
/* do we have a copy? */
q = get(fd);
if (q == NULL) {
/* Try to find a free location */
q = fdinfo.head;
while (q != NULL) {
if (q->fd == -1) {
q->fd = fd;
break;
}
q = q->next;
}
if (q == NULL) {
q = (struct node *) malloc(sizeof(struct node));
if (q == NULL) {
xlog(0, "force_bind: cannot alloc memory"
"; ignore fd!\n");
return;
}
q->next = NULL;
q->fd = fd;
if (fdinfo.tail == NULL) {
fdinfo.head = q;
} else {
fdinfo.tail->next = q;
}
fdinfo.tail = q;
}
}
memcpy(&q->priv, p, sizeof(struct private));
/* Set bandwidth requirements */
q->priv.limit = bw_limit_per_socket;
if (bw_limit_per_socket > 0) {
q->priv.rest = 0;
gettimeofday(&q->priv.last, NULL);
}
list(10);
}
static void del(const int fd)
{
struct node *p;
xlog(2, "force_bind: del(fd=%d)\n", fd);
p = fdinfo.head;
while (p != NULL) {
if (p->fd == fd) {
p->fd = -1;
break;
}
p = p->next;
}
list(2);
}
/* Functions */
static void init(void)
{
static unsigned char inited = 0;
char *x;
if (inited == 1)
return;
inited = 1;
fdinfo.head = NULL;
fdinfo.tail = NULL;
log_file = getenv("FORCE_NET_LOG");
if (log_file != NULL) {
Log = fopen(log_file, "w");
if (Log)
setlinebuf(Log);
} else {
Log = stderr;
}
x = getenv("FORCE_NET_VERBOSE");
if (x != NULL)
verbose = (unsigned int) strtoul(x, NULL, 10);
xlog(1, "force_bind: init started...\n");
xlog(1, "force_bind: version: %s\n", FORCE_BIND_VERSION);
x = getenv("FORCE_BIND_ADDRESS_V4");
if (x != NULL) {
force_address_v4 = x;
xlog(1, "force_bind: conf: binding to IPv4 address \"%s\".\n",
force_address_v4);
}
x = getenv("FORCE_BIND_ADDRESS_V6");
if (x != NULL) {
force_address_v6 = x;
xlog(1, "force_bind: conf: binding to IPv6 address \"%s\".\n",
force_address_v6);
}
/* obsolete mode */
x = getenv("FORCE_BIND_ADDRESS");
if (x != NULL) {
force_address_v4 = x;
force_address_v6 = x;
xlog(1, "force_bind: conf: binding to address \"%s\"."
" Obsolete, use FORCE_BIND_ADDRESS_V4/6.\n",
force_address_v4);
}
x = getenv("FORCE_BIND_PORT_V4");
if (x != NULL) {
force_port_v4 = (int) strtol(x, NULL, 10);
xlog(1, "force_bind: conf: binding to port %d.\n",
force_port_v4);
}
x = getenv("FORCE_BIND_PORT_V6");
if (x != NULL) {
force_port_v6 = (int) strtol(x, NULL, 10);
xlog(1, "force_bind: conf: binding to port %d.\n",
force_port_v6);
}
/* obsolete mode */
x = getenv("FORCE_BIND_PORT");
if (x != NULL) {
force_port_v4 = (int) strtol(x, NULL, 10);
force_port_v6 = (int) strtol(x, NULL, 10);
xlog(1, "force_bind: conf: binding to port %d."
" Obsolete, use FORCE_BIND_PORT_V4/6.\n",
force_port_v4);
}
/* tos */
x = getenv("FORCE_NET_TOS");
if (x != NULL) {
force_tos = 1;
tos = (unsigned int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing TOS to %hhu.\n",
tos);
}
/* ttl */
x = getenv("FORCE_NET_TTL");
if (x != NULL) {
force_ttl = 1;
ttl = (unsigned int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing TTL to %hhu.\n",
ttl);
}
/* keep alive */
x = getenv("FORCE_NET_KA");
if (x != NULL) {
force_keepalive = 1;
keepalive = (unsigned int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing KA to %u.\n",
keepalive);
}
/* mss */
x = getenv("FORCE_NET_MSS");
if (x != NULL) {
force_mss = 1;
mss = (unsigned int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing MSS to %u.\n",
mss);
}
/* REUSEADDR */
x = getenv("FORCE_NET_REUSEADDR");
if (x != NULL) {
force_reuseaddr = 1;
reuseaddr = (unsigned int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing REUSEADDR to %u.\n",
reuseaddr);
}
/* NODELAY */
x = getenv("FORCE_NET_NODELAY");
if (x != NULL) {
force_nodelay = 1;
nodelay = (unsigned int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing NODELAY to %u.\n",
nodelay);
}
/* bandwidth */
x = getenv("FORCE_NET_BW");
if (x != NULL) {
bw_global.limit = (unsigned int) strtoul(x, NULL, 0);
gettimeofday(&bw_global.last, NULL);
bw_global.rest = 0;
xlog(1, "force_bind: conf: forcing bandwidth to %llub/s.\n",
bw_global.limit);
} else {
bw_global.limit = 0;
}
/* bandwidth per socket */
x = getenv("FORCE_NET_BW_PER_SOCKET");
if (x != NULL) {
if (bw_global.limit > 0) {
xlog(1, "force_bind: conf: cannot set limit per socket"
" when global one is set.\n");
} else {
bw_limit_per_socket = (unsigned int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing bandwidth per socket to %llub/s.\n",
bw_limit_per_socket);
}
}
/* IPv6 flowinfo */
x = getenv("FORCE_NET_FLOWINFO");
if (x != NULL) {
force_flowinfo = 1;
flowinfo = (unsigned int) strtoul(x, NULL, 0) & IPV6_FLOWINFO_MASK;
xlog(1, "force_bind: conf: forcing FLOWINFO to 0x%x.\n",
flowinfo);
}
/* fwmark */
x = getenv("FORCE_NET_FWMARK");
if (x != NULL) {
force_fwmark = 1;
fwmark = (unsigned int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing fwmark to 0x%x.\n",
fwmark);
}
/* prio */
x = getenv("FORCE_NET_PRIO");
if (x != NULL) {
force_prio = 1;
prio = (unsigned int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing prio to %u.\n",
prio);
}
/* poll timeout */
x = getenv("FORCE_NET_POLL_TIMEOUT");
if (x != NULL) {
force_poll_timeout = (int) strtoul(x, NULL, 0);
xlog(1, "force_bind: conf: forcing poll timeout to %d.\n",
force_poll_timeout);
}
/******** Now, hijack system calls ********/
old_bind = dlsym(RTLD_NEXT, "bind");
if (old_bind == NULL) {
xlog(0, "force_bind: cannot resolve 'bind'!\n");
exit(1);
}
old_setsockopt = dlsym(RTLD_NEXT, "setsockopt");
if (old_setsockopt == NULL) {
xlog(0, "force_bind: cannot resolve 'setsockopt'!\n");
exit(1);
}
old_socket = dlsym(RTLD_NEXT, "socket");
if (old_socket == NULL) {
xlog(0, "force_bind: cannot resolve 'socket'!\n");
exit(1);
}
old_close = dlsym(RTLD_NEXT, "close");
if (old_close == NULL) {
xlog(0, "force_bind: cannot resolve 'close'!\n");
exit(1);
}
old_write = dlsym(RTLD_NEXT, "write");
if (old_write == NULL) {
xlog(0, "force_bind: cannot resolve 'write'!\n");
exit(1);
}
old_send = dlsym(RTLD_NEXT, "send");
if (old_send == NULL) {
xlog(0, "force_bind: cannot resolve 'send'!\n");
exit(1);
}
old_sendto = dlsym(RTLD_NEXT, "sendto");
if (old_sendto == NULL) {
xlog(0, "force_bind: cannot resolve 'sendto'!\n");
exit(1);
}
old_sendmsg = dlsym(RTLD_NEXT, "sendmsg");
if (old_sendmsg == NULL) {
xlog(0, "force_bind: cannot resolve 'sendmsg'!\n");
exit(1);
}
old_accept = dlsym(RTLD_NEXT, "accept");
if (old_accept == NULL) {
xlog(0, "force_bind: cannot resolve 'accept'!\n");
exit(1);
}
old_accept4 = dlsym(RTLD_NEXT, "accept4");
if (old_accept4 == NULL) {
xlog(0, "force_bind: cannot resolve 'accept4'!\n");
exit(1);
}
old_connect = dlsym(RTLD_NEXT, "connect");
if (old_connect == NULL) {
xlog(0, "force_bind: cannot resolve 'connect'!\n");
exit(1);
}
old_poll = dlsym(RTLD_NEXT, "poll");
if (old_poll == NULL) {
xlog(0, "force_bind: cannot resolve 'poll'!\n");
exit(1);
}
xlog(1, "force_bind: init ended.\n");
}
static int set_ka(int sockfd)
{
int flag, ret;
if (force_keepalive == 0)
return 0;
flag = (keepalive > 0) ? 1 : 0;
ret = old_setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &flag, sizeof(flag));
xlog(1, "force_bind: changing SO_KEEPALIVE to %d (ret=%d(%s)) [%d].\n",
flag, ret, strerror(errno), sockfd);
return ret;
}
static int set_ka_idle(int sockfd)
{
int ret;
if (force_keepalive == 0)
return 0;
ret = old_setsockopt(sockfd, IPPROTO_TCP, TCP_KEEPIDLE, &keepalive, sizeof(keepalive));
xlog(1, "force_bind: changing TCP_KEEPIDLE to %us (ret=%d(%s)) [%d].\n",
keepalive, ret, strerror(errno), sockfd);
return ret;
}
static int set_mss(int sockfd)
{
int ret;
if (force_mss == 0)
return 0;
ret = old_setsockopt(sockfd, IPPROTO_TCP, TCP_MAXSEG, &mss, sizeof(mss));
xlog(1, "force_bind: changing MSS to %u (ret=%d(%s)) [%d].\n",
mss, ret, strerror(errno), sockfd);
return ret;
}
static int set_tos(int sockfd)
{
int ret;
if (force_tos == 0)
return 0;
ret = old_setsockopt(sockfd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
xlog(1, "force_bind: changing TOS to %hhu (ret=%d(%s)) [%d].\n",
tos, ret, strerror(errno), sockfd);
return ret;
}
static int set_ttl(int sockfd)
{
int ret;
if (force_ttl == 0)
return 0;
ret = old_setsockopt(sockfd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
xlog(1, "force_bind: changing TTL to %hhu (ret=%d(%s)) [%d].\n",
ttl, ret, strerror(errno), sockfd);
return ret;
}
static int set_reuseaddr(int sockfd)
{
int ret;
if (force_reuseaddr == 0)
return 0;
ret = old_setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof(reuseaddr));
xlog(1, "force_bind: changing reuseaddr to %u (ret=%d(%s)) [%d].\n",
reuseaddr, ret, strerror(errno), sockfd);
return ret;
}
static int set_nodelay(int sockfd)
{
int ret;
if (force_nodelay == 0)
return 0;
ret = old_setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, &nodelay, sizeof(nodelay));
xlog(1, "force_bind: changing nodelay to %u (ret=%d(%s)) [%d].\n",
nodelay, ret, strerror(errno), sockfd);
return ret;
}
/*
* Set IPv6 flowinfo
*/
static void set_flowinfo(int sockfd, struct private *p)
{
int ret;
int yes;
struct in6_flowlabel_req mgr;
struct sockaddr_in6 *sa6;
if (force_flowinfo == 0)
return;
if (p->domain != AF_INET6)
return;
if ((p->flags & FB_FLAGS_FLOWINFO_CALLED) != 0)
return;
/* In case of error we cannot do anything, anyway */
p->flags |= FB_FLAGS_FLOWINFO_CALLED;
/* Prepare flow */
memset(&mgr, 0, sizeof(mgr));
sa6 = (struct sockaddr_in6 *) &p->dest;
memcpy(&mgr.flr_dst, &sa6->sin6_addr, sizeof(struct in6_addr));
mgr.flr_label = htonl(flowinfo & IPV6_FLOWLABEL_MASK);
mgr.flr_action = IPV6_FL_A_GET;
mgr.flr_share = IPV6_FL_S_ANY;
mgr.flr_flags = IPV6_FL_F_CREATE;
ret = old_setsockopt(sockfd, SOL_IPV6, IPV6_FLOWLABEL_MGR, &mgr, sizeof(mgr));
xlog(1, "force_bind: flow mgr (ret=%d(%s)) [%d].\n",
ret, strerror(errno), sockfd);
yes = 1;
ret = old_setsockopt(sockfd, SOL_IPV6, IPV6_FLOWINFO_SEND, &yes, sizeof(yes));
xlog(1, "force_bind: changing flowinfo to 'yes' (ret=%d(%s)) [%d].\n",
ret, strerror(errno), sockfd);
}
static int set_fwmark(int sockfd)
{
int ret;
if (force_fwmark == 0)
return 0;
ret = old_setsockopt(sockfd, SOL_SOCKET, SO_MARK, &fwmark, sizeof(fwmark));
xlog(1, "force_bind: changing fwmark to 0x%x (ret=%d(%s)) [%d].\n",
fwmark, ret, strerror(errno), sockfd);
return ret;
}
static int set_prio(int sockfd)
{
int ret;
if (force_prio == 0)
return 0;
ret = old_setsockopt(sockfd, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio));
xlog(1, "force_bind: changing fwmark to 0x%x (ret=%d(%s)) [%d].\n",
prio, ret, strerror(errno), sockfd);
return ret;
}
/*
* Alters a struct sockaddr, based on environment variables
* Returns 1 if the struct was altered, 0 otherwise.
*/
static int alter_sa(const int sockfd, struct sockaddr *sa)
{
struct sockaddr_in *sa4;
struct sockaddr_in6 *sa6;
unsigned short *pport = NULL;
void *p;
char *force_address = NULL;
int force_port;
int err, ret = 0;
xlog(2, "force_bind: alter_sa(sockfd=%d, ...)\n", sockfd);
switch (sa->sa_family) {
case AF_INET:
sa4 = (struct sockaddr_in *) sa;
p = &sa4->sin_addr;
pport = &sa4->sin_port;
force_address = force_address_v4;
force_port = force_port_v4;
break;
case AF_INET6:
sa6 = (struct sockaddr_in6 *) sa;
p = &sa6->sin6_addr.s6_addr;
pport = &sa6->sin6_port;
force_address = force_address_v6;
force_port = force_port_v6;
break;
default:
xlog(1, "force_bind: unsupported family=%u [%d]!\n",
sa->sa_family, sockfd);
return 0;
}
if (force_address != NULL) {
err = inet_pton(sa->sa_family, force_address, p);
if (err != 1) {
xlog(1, "force_bind: cannot convert [%s] (%d) (%s) [%d]!\n",
force_address, err, strerror(errno), sockfd);
return 0;
}
ret = 1;
}
if (force_port != -1) {
*pport = htons(force_port);
ret = 1;
}
return ret;
}
/*
* Alter destination sa
*/
static void alter_dest_sa(int sockfd, struct sockaddr_storage *ss, socklen_t len)
{
struct node *q;
struct sockaddr_in6 *sa6;
char addr[128];
init();
saddr(addr, sizeof(addr), ss);
xlog(2, "force_bind: alter_dest_sa(sockfd=%d, addr=%s)\n",
sockfd, addr);
/* We do not touch non network sockets */
q = get(sockfd);
if ((q == NULL) || ((q->priv.flags & FB_FLAGS_NETSOCK) == 0))
return;
switch (ss->ss_family) {
case AF_INET6:
sa6 = (struct sockaddr_in6 *) ss;
if (force_flowinfo == 1) {
xlog(1, "force_bind: changing flowinfo from 0x%x to 0x%x [%d]!\n",
ntohl(sa6->sin6_flowinfo), flowinfo, sockfd);
sa6->sin6_flowinfo = htonl(flowinfo);
}
break;
}
memcpy(&q->priv.dest, ss, len);
q->priv.dest_len = len;
set_flowinfo(sockfd, &q->priv);
}
/*
* Alter local binding by doing a forced 'bind' call.
* This is called before calling connect and before using sendto/sendmsg.
*/
static void change_local_binding(int sockfd)
{
int err;
struct node *q;
struct sockaddr_storage tmp;
socklen_t tmp_len;
init();
xlog(2, "force_bind: change_local_binding(sockfd=%d)\n", sockfd);
/* We do not touch non network sockets */
q = get(sockfd);
if ((q == NULL) || ((q->priv.flags & FB_FLAGS_NETSOCK) == 0))
return;
/* We do not touch already binded sockets */
if ((q->priv.flags & FB_FLAGS_BIND_CALLED) != 0)
return;
tmp_len = sizeof(struct sockaddr_storage);
err = getsockname(sockfd, (struct sockaddr *) &tmp, &tmp_len);
if (err != 0) {
xlog(1, "force_bind: cannot get socket name err=%d (%s) [%d]!\n",
err, strerror(errno), sockfd);
return;
}
if (alter_sa(sockfd, (struct sockaddr *) &tmp) == 0)
return;
err = old_bind(sockfd, (struct sockaddr *) &tmp, tmp_len);
q->priv.flags |= FB_FLAGS_BIND_CALLED;
if (err != 0)
xlog(1, "force_bind: cannot bind err=%d (%s) [%d]!\n",
err, strerror(errno), sockfd);
}
int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen)
{
struct node *q;
struct sockaddr_storage new;
char *force_address = "";
char tmp[128];
init();
saddr(tmp, sizeof(tmp), (struct sockaddr_storage *) addr);
xlog(1, "force_bind: bind(sockfd=%d, %s)\n", sockfd, tmp);
memcpy(&new, addr, addrlen);
/* We do not touch non network sockets */
q = get(sockfd);
do {
if (q == NULL)
break;
if ((q->priv.flags & FB_FLAGS_NETSOCK) == 0)
break;
switch (q->priv.domain) {
case AF_INET: force_address = force_address_v4; break;
case AF_INET6: force_address = force_address_v6; break;
}
/* Test if we should deny the bind */
if (force_address && (strcmp(force_address, "deny") == 0)) {
xlog(1, "force_bind: deny binding to %s\n", tmp);
errno = EACCES;
return -1;
}
if (force_address && (strcmp(force_address, "fake") == 0)) {
xlog(1, "force_bind: fake binding to %s\n", tmp);
return 0;
}
alter_sa(sockfd, (struct sockaddr *) &new);
q->priv.flags |= FB_FLAGS_BIND_CALLED;
} while (0);
return old_bind(sockfd, (struct sockaddr *) &new, addrlen);
}
int setsockopt(int sockfd, int level, int optname, const void *optval,
socklen_t optlen)
{
init();
if (level == SOL_SOCKET) {
if (optname == SO_KEEPALIVE)
return set_ka(sockfd);
if (optname == SO_REUSEADDR)
return set_reuseaddr(sockfd);
if (optname == SO_MARK)
return set_fwmark(sockfd);
if (optname == SO_PRIORITY)
return set_prio(sockfd);
}
if (level == IPPROTO_IP) {
if (optname == IP_TOS)
return set_tos(sockfd);
if (optname == IP_TTL)
return set_ttl(sockfd);
}
if (level == IPPROTO_TCP) {
if (optname == TCP_KEEPIDLE)
return set_ka_idle(sockfd);
if (optname == TCP_MAXSEG)
return set_mss(sockfd);
if (optname == TCP_NODELAY)
return set_nodelay(sockfd);
}