* 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 <string.h>
#include <errno.h>
#include <sys/socket.h>
+#include <sys/wait.h>
#include "util.h"
+#include "unaligned.h"
+#include "ipaddr.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;
struct cloc loc;
uint16_t port;
int fd;
+ string_t authbind;
struct buffer_if *rbuf;
struct notify_list *notify;
+ bool_t use_proxy;
+ struct sockaddr_in proxy;
};
static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
(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 (memcmp(&from.sin_addr,&st->proxy.sin_addr,4)!=0 ||
+ memcmp(&from.sin_port,&st->proxy.sin_port,2)!=0) {
+ Message(M_INFO,"udp: received packet that's not "
+ "from the proxy\n");
+ BUF_FREE(st->rbuf);
+ continue;
+ }
+ memcpy(&from.sin_addr,buf_unprepend(st->rbuf,4),4);
+ buf_unprepend(st->rbuf,2);
+ memcpy(&from.sin_port,buf_unprepend(st->rbuf,2),2);
+ }
done=False;
for (n=st->notify; n; n=n->next) {
if (n->fn(n->state, st->rbuf, &from)) {
}
}
if (!done) {
- /* XXX manufacture and send NAK packet */
- Message(M_WARNING,"Need to send NAK\n");
+ uint32_t source,dest;
+ /* Manufacture and send NAK packet */
+ source=get_uint32(st->rbuf->start); /* Us */
+ dest=get_uint32(st->rbuf->start+4); /* Them */
+ Message(M_INFO,"udp (port %d): sending NAK\n",st->port);
+ buffer_init(st->rbuf,0);
+ buf_append_uint32(st->rbuf,dest);
+ buf_append_uint32(st->rbuf,source);
+ buf_append_uint32(st->rbuf,0); /* NAK is msg type 0 */
+ sendto(st->fd, st->rbuf->start, st->rbuf->size, 0,
+ (struct sockaddr *)&from, sizeof(from));
BUF_FREE(st->rbuf);
}
BUF_ASSERT_FREE(st->rbuf);
struct sockaddr_in *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->start-8;
+ memcpy(sa,&dest->sin_addr,4);
+ memset(sa+4,0,4);
+ memcpy(sa+6,&dest->sin_port,2);
+ sendto(st->fd,sa,buf->size+8,0,(struct sockaddr *)&st->proxy,
+ sizeof(st->proxy));
+ } else {
+ sendto(st->fd, buf->start, buf->size, 0,
+ (struct sockaddr *)dest, sizeof(*dest));
+ }
return True;
}
memset(&addr, 0, sizeof(addr));
addr.sin_family=AF_INET;
addr.sin_port=htons(st->port);
- if (bind(st->fd, (struct sockaddr *)&addr, sizeof(addr))!=0) {
- fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line);
+ 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];
+ argv[0]=st->authbind;
+ argv[1]=strdup("00000000");
+ if (!argv[1]) exit(ENOMEM);
+ argv[2]=alloca(8);
+ if (!argv[2]) exit(ENOMEM);
+ sprintf(argv[2],"%04X",htons(st->port));
+ argv[3]=NULL;
+ dup2(st->fd,0);
+ execvp(st->authbind,argv);
+ exit(ENOEXEC);
+ }
+ waitpid(c,&status,0);
+ if (WEXITSTATUS(status)!=0) {
+ errno=WEXITSTATUS(status);
+ fatal_perror("udp (%s:%d): authbind",st->loc.file,st->loc.line);
+ }
+ } else {
+ if (bind(st->fd, (struct sockaddr *)&addr, sizeof(addr))!=0) {
+ fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line);
+ }
}
register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp");
struct udp *st;
item_t *i;
dict_t *d;
+ list_t *l;
+ uint32_t a;
st=safe_malloc(sizeof(*st),"udp_apply(st)");
st->loc=loc;
st->cl.apply=NULL;
st->cl.interface=&st->ops;
st->ops.st=st;
+ st->ops.min_start_pad=0;
+ st->ops.min_end_pad=0;
st->ops.request_notify=request_notify;
st->ops.release_notify=release_notify;
st->ops.sendmsg=udp_sendmsg;
st->port=0;
+ st->use_proxy=False;
i=list_elem(args,0);
if (!i || i->type!=t_dict) {
st->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->authbind=dict_read_string(d,"authbind",False,"udp",st->loc);
+ l=dict_lookup(d,"proxy");
+ if (l) {
+ st->use_proxy=True;
+ memset(&st->proxy,0,sizeof(st->proxy));
+ st->proxy.sin_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_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_port=htons(i->data.number);
+ st->ops.min_start_pad=8;
+ }
add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
~ian / secnet.git / blobdiff