* optionally bind to a particular local IP address (not implemented
* yet).
*
- * Sites register an interest in local port numbers for receiving
- * packets, and can also send packets. We don't care about the source
- * port number for sending packets.
- *
* Packets are offered to registered receivers in turn. Once one
* accepts it, it isn't offered to any more. */
+#include "secnet.h"
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
-#include <sys/types.h>
#include <sys/socket.h>
+#include <sys/wait.h>
#include <netinet/in.h>
-
-#include "secnet.h"
+#include <arpa/inet.h>
#include "util.h"
+#include "magic.h"
+#include "unaligned.h"
+#include "ipaddr.h"
+#include "magic.h"
static beforepoll_fn udp_beforepoll;
static afterpoll_fn udp_afterpoll;
static comm_release_notify_fn release_notify;
static comm_sendmsg_fn udp_sendmsg;
-/* The UDP module exports a pure closure which can be used to construct a
- * UDP send/receive module. Arguments:
- */
-
struct notify_list {
comm_notify_fn *fn;
void *state;
closure_t cl;
struct comm_if ops;
struct cloc loc;
+ union iaddr addr;
int fd;
+ string_t authbind;
struct buffer_if *rbuf;
struct notify_list *notify;
+ bool_t use_proxy;
+ union iaddr proxy;
};
+static const char *addr_to_string(void *commst, const struct comm_addr *ca) {
+ struct udp *st=commst;
+ static char sbuf[100];
+
+ snprintf(sbuf, sizeof(sbuf), "udp:%s-%s",
+ iaddr_to_string(&st->addr), iaddr_to_string(&ca->ia));
+ return sbuf;
+}
+
static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
- int *timeout_io, const struct timeval *tv,
- uint64_t *now)
+ int *timeout_io)
{
struct udp *st=state;
if (*nfds_io<1) {
return 0;
}
-static void udp_afterpoll(void *state, struct pollfd *fds, int nfds,
- const struct timeval *tv, uint64_t *now)
+static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
{
struct udp *st=state;
- struct sockaddr_in from;
- int fromlen;
+ union iaddr from;
+ socklen_t fromlen;
struct notify_list *n;
bool_t done;
int rv;
if (nfds && (fds->revents & POLLIN)) {
do {
+ FILLZERO(from);
fromlen=sizeof(from);
BUF_ASSERT_FREE(st->rbuf);
BUF_ALLOC(st->rbuf,"udp_afterpoll");
- rv=recvfrom(st->fd, st->rbuf->start, st->rbuf->len, 0,
- (struct sockaddr *)&from, &fromlen);
+ buffer_init(st->rbuf,calculate_max_start_pad());
+ rv=recvfrom(st->fd, st->rbuf->start,
+ buf_remaining_space(st->rbuf),
+ 0, (struct sockaddr *)&from, &fromlen);
if (rv>0) {
st->rbuf->size=rv;
+ if (st->use_proxy) {
+ /* Check that the packet came from our poxy server;
+ we shouldn't be contacted directly by anybody else
+ (since they can trivially forge source addresses) */
+ if (!iaddr_equal(&from,&st->proxy)) {
+ Message(M_INFO,"udp: received packet that's not "
+ "from the proxy\n");
+ BUF_FREE(st->rbuf);
+ continue;
+ }
+ /* proxy protocol supports ipv4 transport only */
+ FILLZERO(from);
+ from.sa.sa_family=AF_INET;
+ memcpy(&from.sin.sin_addr,buf_unprepend(st->rbuf,4),4);
+ buf_unprepend(st->rbuf,2);
+ memcpy(&from.sin.sin_port,buf_unprepend(st->rbuf,2),2);
+ }
+ struct comm_addr ca;
+ FILLZERO(ca);
+ ca.comm=&st->ops;
+ ca.ia=from;
done=False;
for (n=st->notify; n; n=n->next) {
- if (n->fn(n->state, st->rbuf, &from)) {
+ if (n->fn(n->state, st->rbuf, &ca)) {
done=True;
break;
}
}
if (!done) {
- /* XXX manufacture and send NAK packet */
- Message(M_WARNING,"Need to send NAK\n");
+ uint32_t msgtype;
+ if (st->rbuf->size>12 /* prevents traffic amplification */
+ && ((msgtype=get_uint32(st->rbuf->start+8))
+ != LABEL_NAK)) {
+ uint32_t source,dest;
+ /* Manufacture and send NAK packet */
+ source=get_uint32(st->rbuf->start); /* Us */
+ dest=get_uint32(st->rbuf->start+4); /* Them */
+ send_nak(&ca,source,dest,msgtype,st->rbuf,"unwanted");
+ }
BUF_FREE(st->rbuf);
}
BUF_ASSERT_FREE(st->rbuf);
}
static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
- struct sockaddr_in *dest)
+ const struct comm_addr *dest)
{
struct udp *st=commst;
+ uint8_t *sa;
- /* XXX fix error reporting */
- sendto(st->fd, buf->start, buf->size, 0,
- (struct sockaddr *)dest, sizeof(*dest));
+ if (st->use_proxy) {
+ sa=buf_prepend(buf,8);
+ if (dest->ia.sa.sa_family != AF_INET) {
+ Message(M_INFO,
+ "udp: proxy means dropping outgoing non-IPv4 packet to %s\n",
+ iaddr_to_string(&dest->ia));
+ return False;
+ }
+ memcpy(sa,&dest->ia.sin.sin_addr,4);
+ memset(sa+4,0,4);
+ memcpy(sa+6,&dest->ia.sin.sin_port,2);
+ sendto(st->fd,sa,buf->size+8,0,(struct sockaddr *)&st->proxy,
+ sizeof(st->proxy));
+ buf_unprepend(buf,8);
+ } else {
+ sendto(st->fd, buf->start, buf->size, 0,
+ &dest->ia.sa, iaddr_socklen(&dest->ia));
+ }
return True;
}
+static void udp_make_socket(struct udp *st, struct udp *us)
+{
+ const union iaddr *addr=&us->addr;
+ us->fd=socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
+ if (us->fd<0) {
+ fatal_perror("udp (%s:%d): socket",st->loc.file,st->loc.line);
+ }
+ if (fcntl(us->fd, F_SETFL, fcntl(us->fd, F_GETFL)|O_NONBLOCK)==-1) {
+ fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
+ st->loc.file,st->loc.line);
+ }
+ setcloexec(us->fd);
+
+ if (st->authbind) {
+ pid_t c;
+ int status;
+
+ /* XXX this fork() and waitpid() business needs to be hidden
+ in some system-specific library functions. */
+ c=fork();
+ if (c==-1) {
+ fatal_perror("udp_phase_hook: fork() for authbind");
+ }
+ if (c==0) {
+ char *argv[4], addrstr[9], portstr[5];
+ switch (addr->sa.sa_family) {
+ case AF_INET:
+ sprintf(addrstr,"%08lX",(long)addr->sin.sin_addr.s_addr);
+ sprintf(portstr,"%04X",addr->sin.sin_port);
+ break;
+ default:
+ fatal("udp (%s:%d): unsupported address family for authbind",
+ st->loc.file,st->loc.line);
+ }
+ argv[0]=st->authbind;
+ argv[1]=addrstr;
+ argv[2]=portstr;
+ argv[3]=NULL;
+ dup2(us->fd,0);
+ execvp(st->authbind,argv);
+ _exit(255);
+ }
+ while (waitpid(c,&status,0)==-1) {
+ if (errno==EINTR) continue;
+ fatal_perror("udp (%s:%d): authbind",st->loc.file,st->loc.line);
+ }
+ if (WIFSIGNALED(status)) {
+ fatal("udp (%s:%d): authbind died on signal %d",st->loc.file,
+ st->loc.line, WTERMSIG(status));
+ }
+ if (WIFEXITED(status) && WEXITSTATUS(status)!=0) {
+ fatal("udp (%s:%d): authbind died with status %d",st->loc.file,
+ st->loc.line, WEXITSTATUS(status));
+ }
+ } else {
+ if (bind(us->fd, &addr->sa, iaddr_socklen(addr))!=0) {
+ fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line);
+ }
+ }
+}
+
+static void udp_phase_hook(void *sst, uint32_t new_phase)
+{
+ struct udp *st=sst;
+ udp_make_socket(st,st);
+ register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp");
+}
+
static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
list_t *args)
{
struct udp *st;
- item_t *i;
+ item_t *i,*j;
dict_t *d;
- uint16_t local_port=0;
- struct sockaddr_in addr;
+ list_t *l;
+ uint32_t a;
st=safe_malloc(sizeof(*st),"udp_apply(st)");
st->loc=loc;
st->ops.request_notify=request_notify;
st->ops.release_notify=release_notify;
st->ops.sendmsg=udp_sendmsg;
+ st->ops.addr_to_string=addr_to_string;
+ FILLZERO(st->addr);
+ st->use_proxy=False;
i=list_elem(args,0);
if (!i || i->type!=t_dict) {
}
d=i->data.dict;
- local_port=dict_read_number(d,"port",False,"udp",st->loc,0);
+ st->addr.sa.sa_family=AF_INET;
+ j=dict_find_item(d,"address",False,"udp",st->loc);
+ st->addr.sin.sin_addr.s_addr=j?string_item_to_ipaddr(j, "udp"):INADDR_ANY;
+ st->addr.sin.sin_port=dict_read_number(d,"port",True,"udp",st->loc,0);
st->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,"udp",st->loc);
-
- st->fd=socket(AF_INET, SOCK_DGRAM, 0);
- if (st->fd<0) {
- fatal_perror("udp_apply (%s:%d): socket",loc.file,loc.line);
- }
- if (fcntl(st->fd, F_SETFL, fcntl(st->fd, F_GETFL)|O_NONBLOCK)==-1) {
- fatal_perror("udp_apply (%s:%d): fcntl(set O_NONBLOCK)",
- loc.file,loc.line);
- }
- if (fcntl(st->fd, F_SETFD, FD_CLOEXEC)==-1) {
- fatal_perror("udp_apply (%s:%d): fcntl(set FD_CLOEXEC)",
- loc.file,loc.line);
+ st->authbind=dict_read_string(d,"authbind",False,"udp",st->loc);
+ l=dict_lookup(d,"proxy");
+ if (l) {
+ st->use_proxy=True;
+ FILLZERO(st->proxy);
+ st->proxy.sa.sa_family=AF_INET;
+ i=list_elem(l,0);
+ if (!i || i->type!=t_string) {
+ cfgfatal(st->loc,"udp","proxy must supply ""addr"",port\n");
+ }
+ a=string_item_to_ipaddr(i,"proxy");
+ st->proxy.sin.sin_addr.s_addr=htonl(a);
+ i=list_elem(l,1);
+ if (!i || i->type!=t_number) {
+ cfgfatal(st->loc,"udp","proxy must supply ""addr"",port\n");
+ }
+ st->proxy.sin.sin_port=htons(i->data.number);
}
- memset(&addr, 0, sizeof(addr));
- addr.sin_family=AF_INET;
- if (local_port) {
- addr.sin_port=htons(local_port);
- }
- if (bind(st->fd, (struct sockaddr *)&addr, sizeof(addr))!=0) {
- fatal_perror("udp_apply (%s:%d): bind",loc.file,loc.line);
- }
+ update_max_start_pad(&comm_max_start_pad, st->use_proxy ? 8 : 0);
- register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp");
+ add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
return new_closure(&st->cl);
}
-init_module udp_module;
void udp_module(dict_t *dict)
{
add_closure(dict,"udp",udp_apply);
~ian / secnet.git / blobdiff