[secnet] / udp.c

/* UDP send/receive module for secnet */

/* This module enables sites to communicate by sending UDP
 * packets. When an instance of the module is created we can
 * optionally bind to a particular local IP address (not implemented
 * yet).
 *
 * 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/socket.h>
#include <sys/wait.h>
#include <netinet/in.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_request_notify_fn request_notify;
static comm_release_notify_fn release_notify;
static comm_sendmsg_fn udp_sendmsg;

struct notify_list {
    comm_notify_fn *fn;
    void *state;
    struct notify_list *next;
};

struct udp {
    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)
{
    struct udp *st=state;
    if (*nfds_io<1) {
	*nfds_io=1;
	return ERANGE;
    }
    *nfds_io=1;
    fds->fd=st->fd;
    fds->events=POLLIN;
    return 0;
}

static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
{
    struct udp *st=state;
    union iaddr from;
    socklen_t fromlen;
    struct notify_list *n;
    bool_t done;
    int rv;

    if (nfds && (fds->revents & POLLIN)) {
	do {
	    fromlen=sizeof(from);
	    BUF_ASSERT_FREE(st->rbuf);
	    BUF_ALLOC(st->rbuf,"udp_afterpoll");
	    buffer_init(st->rbuf,calculate_max_start_pad());
	    rv=recvfrom(st->fd, st->rbuf->start,
			buf_remaining_space(st->rbuf),
			0, &from.sa, &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 */
		    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;
		ca.comm=&st->ops;
		ca.ia=from;
		done=False;
		for (n=st->notify; n; n=n->next) {
		    if (n->fn(n->state, st->rbuf, &ca)) {
			done=True;
			break;
		    }
		}
		if (!done) {
		    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);
	    } else {
		BUF_FREE(st->rbuf);
	    }
	} while (rv>=0);
    }
}

static void request_notify(void *commst, void *nst, comm_notify_fn *fn)
{
    struct udp *st=commst;
    struct notify_list *n;
    
    n=safe_malloc(sizeof(*n),"request_notify");
    n->fn=fn;
    n->state=nst;
    n->next=st->notify;
    st->notify=n;
}

static void release_notify(void *commst, void *nst, comm_notify_fn *fn)
{
    struct udp *st=commst;
    struct notify_list *n, **p, *t;

    /* XXX untested */
    p=&st->notify;
    for (n=st->notify; n; )
    {
	if (n->state==nst && n->fn==fn) {
	    t=n;
	    *p=n->next;
	    n=n->next;
	    free(t);
	} else {
	    p=&n->next;
	    n=n->next;
	}
    }
}

static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
			  const struct comm_addr *dest)
{
    struct udp *st=commst;
    uint8_t *sa;

    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,&st->proxy.sa,
	       iaddr_socklen(&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_phase_hook(void *sst, uint32_t new_phase)
{
    struct udp *st=sst;
    union iaddr addr;

    st->fd=socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (st->fd<0) {
	fatal_perror("udp (%s:%d): socket",st->loc.file,st->loc.line);
    }
    if (fcntl(st->fd, F_SETFL, fcntl(st->fd, F_GETFL)|O_NONBLOCK)==-1) {
	fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
		     st->loc.file,st->loc.line);
    }
    setcloexec(st->fd);

    addr=st->addr;
    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(st->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(st->fd, &addr.sa, iaddr_socklen(&addr))!=0) {
	    fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line);
	}
    }

    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,*j;
    dict_t *d;
    list_t *l;
    uint32_t a;

    st=safe_malloc(sizeof(*st),"udp_apply(st)");
    st->loc=loc;
    st->cl.description="udp";
    st->cl.type=CL_COMM;
    st->cl.apply=NULL;
    st->cl.interface=&st->ops;
    st->ops.st=st;
    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;
    st->use_proxy=False;

    i=list_elem(args,0);
    if (!i || i->type!=t_dict) {
	cfgfatal(st->loc,"udp","first argument must be a dictionary\n");
    }
    d=i->data.dict;

    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->authbind=dict_read_string(d,"authbind",False,"udp",st->loc);
    l=dict_lookup(d,"proxy");
    if (l) {
	st->use_proxy=True;
	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);
    }

    update_max_start_pad(&comm_max_start_pad, st->use_proxy ? 8 : 0);

    add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);

    return new_closure(&st->cl);
}

void udp_module(dict_t *dict)
{
    add_closure(dict,"udp",udp_apply);
}
Commit	Line	Data
2fe58dfd SE	1	/* UDP send/receive module for secnet */
	2
	3	/* This module enables sites to communicate by sending UDP
	4	* packets. When an instance of the module is created we can
	5	* optionally bind to a particular local IP address (not implemented
	6	* yet).
	7	*
2fe58dfd SE	8	* Packets are offered to registered receivers in turn. Once one
	9	* accepts it, it isn't offered to any more. */
	10
8689b3a9	11	#include "secnet.h"
2fe58dfd SE	12	#include <stdio.h>
	13	#include <unistd.h>
	14	#include <fcntl.h>
	15	#include <string.h>
	16	#include <errno.h>
2fe58dfd	17	#include <sys/socket.h>
b2a56f7c	18	#include <sys/wait.h>
5edf478f IJ	19	#include <netinet/in.h>
5edf478f IJ	20	#include <arpa/inet.h>
2fe58dfd	21	#include "util.h"
dd9209d1	22	#include "magic.h"
794f2398	23	#include "unaligned.h"
ff05a229	24	#include "ipaddr.h"
136740e6	25	#include "magic.h"
2fe58dfd SE	26
	27	static beforepoll_fn udp_beforepoll;
	28	static afterpoll_fn udp_afterpoll;
	29	static comm_request_notify_fn request_notify;
	30	static comm_release_notify_fn release_notify;
	31	static comm_sendmsg_fn udp_sendmsg;
	32
2fe58dfd SE	33	struct notify_list {
	34	comm_notify_fn *fn;
	35	void *state;
	36	struct notify_list *next;
	37	};
	38
	39	struct udp {
	40	closure_t cl;
	41	struct comm_if ops;
	42	struct cloc loc;
a32d56fb	43	union iaddr addr;
2fe58dfd	44	int fd;
b2a56f7c	45	string_t authbind;
2fe58dfd SE	46	struct buffer_if *rbuf;
2fe58dfd SE	47	struct notify_list *notify;
ff05a229	48	bool_t use_proxy;
a32d56fb	49	union iaddr proxy;
2fe58dfd SE	50	};
2fe58dfd SE	51
5edf478f IJ	52	static const char addr_to_string(void commst, const struct comm_addr *ca) {
	53	struct udp *st=commst;
	54	static char sbuf[100];
	55
5edf478f	56	snprintf(sbuf, sizeof(sbuf), "udp:%s-%s",
a32d56fb	57	iaddr_to_string(&st->addr), iaddr_to_string(&ca->ia));
5edf478f IJ	58	return sbuf;
	59	}
	60
2fe58dfd	61	static int udp_beforepoll(void state, struct pollfd fds, int *nfds_io,
90a39563	62	int *timeout_io)
2fe58dfd SE	63	{
	64	struct udp *st=state;
	65	if (*nfds_io<1) {
	66	*nfds_io=1;
	67	return ERANGE;
	68	}
	69	*nfds_io=1;
	70	fds->fd=st->fd;
	71	fds->events=POLLIN;
	72	return 0;
	73	}
	74
90a39563	75	static void udp_afterpoll(void state, struct pollfd fds, int nfds)
2fe58dfd SE	76	{
2fe58dfd SE	77	struct udp *st=state;
a32d56fb	78	union iaddr from;
b1a0f651	79	socklen_t fromlen;
2fe58dfd SE	80	struct notify_list *n;
	81	bool_t done;
	82	int rv;
	83
	84	if (nfds && (fds->revents & POLLIN)) {
	85	do {
	86	fromlen=sizeof(from);
	87	BUF_ASSERT_FREE(st->rbuf);
	88	BUF_ALLOC(st->rbuf,"udp_afterpoll");
6af9a984	89	buffer_init(st->rbuf,calculate_max_start_pad());
1b4ca45e	90	rv=recvfrom(st->fd, st->rbuf->start,
92795040	91	buf_remaining_space(st->rbuf),
a32d56fb	92	0, &from.sa, &fromlen);
2fe58dfd SE	93	if (rv>0) {
2fe58dfd SE	94	st->rbuf->size=rv;
ff05a229 SE	95	if (st->use_proxy) {
	96	/* Check that the packet came from our poxy server;
	97	we shouldn't be contacted directly by anybody else
	98	(since they can trivially forge source addresses) */
a32d56fb	99	if (!iaddr_equal(&from,&st->proxy)) {
ff05a229 SE	100	Message(M_INFO,"udp: received packet that's not "
	101	"from the proxy\n");
	102	BUF_FREE(st->rbuf);
	103	continue;
	104	}
a32d56fb IJ	105	/* proxy protocol supports ipv4 transport only */
	106	from.sa.sa_family=AF_INET;
	107	memcpy(&from.sin.sin_addr,buf_unprepend(st->rbuf,4),4);
ff05a229	108	buf_unprepend(st->rbuf,2);
a32d56fb	109	memcpy(&from.sin.sin_port,buf_unprepend(st->rbuf,2),2);
ff05a229	110	}
8534d602	111	struct comm_addr ca;
8534d602	112	ca.comm=&st->ops;
a32d56fb	113	ca.ia=from;
2fe58dfd SE	114	done=False;
2fe58dfd SE	115	for (n=st->notify; n; n=n->next) {
a15faeb2	116	if (n->fn(n->state, st->rbuf, &ca)) {
2fe58dfd SE	117	done=True;
	118	break;
	119	}
	120	}
	121	if (!done) {
bf28fc73 IJ	122	uint32_t msgtype;
	123	if (st->rbuf->size>12 /* prevents traffic amplification */
	124	&& ((msgtype=get_uint32(st->rbuf->start+8))
	125	!= LABEL_NAK)) {
	126	uint32_t source,dest;
	127	/* Manufacture and send NAK packet */
	128	source=get_uint32(st->rbuf->start); /* Us */
	129	dest=get_uint32(st->rbuf->start+4); /* Them */
8534d602	130	send_nak(&ca,source,dest,msgtype,st->rbuf,"unwanted");
bf28fc73	131	}
2fe58dfd SE	132	BUF_FREE(st->rbuf);
	133	}
	134	BUF_ASSERT_FREE(st->rbuf);
	135	} else {
	136	BUF_FREE(st->rbuf);
	137	}
	138	} while (rv>=0);
	139	}
	140	}
	141
	142	static void request_notify(void commst, void nst, comm_notify_fn *fn)
	143	{
	144	struct udp *st=commst;
	145	struct notify_list *n;
	146
	147	n=safe_malloc(sizeof(*n),"request_notify");
	148	n->fn=fn;
	149	n->state=nst;
	150	n->next=st->notify;
	151	st->notify=n;
	152	}
	153
	154	static void release_notify(void commst, void nst, comm_notify_fn *fn)
	155	{
	156	struct udp *st=commst;
	157	struct notify_list n, p, t;
	158
	159	/* XXX untested */
	160	p=&st->notify;
	161	for (n=st->notify; n; )
	162	{
	163	if (n->state==nst && n->fn==fn) {
	164	t=n;
	165	*p=n->next;
	166	n=n->next;
	167	free(t);
	168	} else {
	169	p=&n->next;
	170	n=n->next;
	171	}
	172	}
	173	}
	174
	175	static bool_t udp_sendmsg(void commst, struct buffer_if buf,
a15faeb2	176	const struct comm_addr *dest)
2fe58dfd SE	177	{
2fe58dfd SE	178	struct udp *st=commst;
ff05a229	179	uint8_t *sa;
2fe58dfd	180
ff05a229	181	if (st->use_proxy) {
3abd18e8	182	sa=buf_prepend(buf,8);
a32d56fb IJ	183	if (dest->ia.sa.sa_family != AF_INET) {
	184	Message(M_INFO,
	185	"udp: proxy means dropping outgoing non-IPv4 packet to %s\n",
	186	iaddr_to_string(&dest->ia));
	187	return False;
	188	}
	189	memcpy(sa,&dest->ia.sin.sin_addr,4);
ff05a229	190	memset(sa+4,0,4);
a32d56fb IJ	191	memcpy(sa+6,&dest->ia.sin.sin_port,2);
	192	sendto(st->fd,sa,buf->size+8,0,&st->proxy.sa,
	193	iaddr_socklen(&st->proxy));
3abd18e8	194	buf_unprepend(buf,8);
ff05a229 SE	195	} else {
ff05a229 SE	196	sendto(st->fd, buf->start, buf->size, 0,
a32d56fb	197	&dest->ia.sa, iaddr_socklen(&dest->ia));
ff05a229	198	}
2fe58dfd SE	199
	200	return True;
	201	}
	202
baa06aeb SE	203	static void udp_phase_hook(void *sst, uint32_t new_phase)
	204	{
	205	struct udp *st=sst;
a32d56fb	206	union iaddr addr;
baa06aeb	207
3b83c932	208	st->fd=socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
baa06aeb SE	209	if (st->fd<0) {
	210	fatal_perror("udp (%s:%d): socket",st->loc.file,st->loc.line);
	211	}
	212	if (fcntl(st->fd, F_SETFL, fcntl(st->fd, F_GETFL)\|O_NONBLOCK)==-1) {
	213	fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
	214	st->loc.file,st->loc.line);
	215	}
4fb0f88d	216	setcloexec(st->fd);
baa06aeb	217
a32d56fb	218	addr=st->addr;
b2a56f7c SE	219	if (st->authbind) {
	220	pid_t c;
	221	int status;
	222
	223	/* XXX this fork() and waitpid() business needs to be hidden
	224	in some system-specific library functions. */
	225	c=fork();
	226	if (c==-1) {
	227	fatal_perror("udp_phase_hook: fork() for authbind");
	228	}
	229	if (c==0) {
3b83c932	230	char *argv[4], addrstr[9], portstr[5];
a32d56fb IJ	231	switch (addr.sa.sa_family) {
	232	case AF_INET:
	233	sprintf(addrstr,"%08lX",(long)addr.sin.sin_addr.s_addr);
	234	sprintf(portstr,"%04X",addr.sin.sin_port);
	235	break;
	236	default:
	237	fatal("udp (%s:%d): unsupported address family for authbind",
	238	st->loc.file,st->loc.line);
	239	}
b2a56f7c	240	argv[0]=st->authbind;
3b83c932 SE	241	argv[1]=addrstr;
3b83c932 SE	242	argv[2]=portstr;
b2a56f7c SE	243	argv[3]=NULL;
	244	dup2(st->fd,0);
	245	execvp(st->authbind,argv);
3b83c932	246	_exit(255);
b2a56f7c	247	}
3b83c932 SE	248	while (waitpid(c,&status,0)==-1) {
3b83c932 SE	249	if (errno==EINTR) continue;
b2a56f7c SE	250	fatal_perror("udp (%s:%d): authbind",st->loc.file,st->loc.line);
b2a56f7c SE	251	}
3b83c932 SE	252	if (WIFSIGNALED(status)) {
	253	fatal("udp (%s:%d): authbind died on signal %d",st->loc.file,
	254	st->loc.line, WTERMSIG(status));
	255	}
	256	if (WIFEXITED(status) && WEXITSTATUS(status)!=0) {
	257	fatal("udp (%s:%d): authbind died with status %d",st->loc.file,
	258	st->loc.line, WEXITSTATUS(status));
	259	}
b2a56f7c	260	} else {
a32d56fb	261	if (bind(st->fd, &addr.sa, iaddr_socklen(&addr))!=0) {
b2a56f7c SE	262	fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line);
b2a56f7c SE	263	}
baa06aeb SE	264	}
	265
	266	register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp");
	267	}
	268
2fe58dfd SE	269	static list_t udp_apply(closure_t self, struct cloc loc, dict_t *context,
	270	list_t *args)
	271	{
	272	struct udp *st;
3b83c932	273	item_t i,j;
2fe58dfd	274	dict_t *d;
ff05a229 SE	275	list_t *l;
ff05a229 SE	276	uint32_t a;
2fe58dfd SE	277
	278	st=safe_malloc(sizeof(*st),"udp_apply(st)");
	279	st->loc=loc;
	280	st->cl.description="udp";
	281	st->cl.type=CL_COMM;
	282	st->cl.apply=NULL;
	283	st->cl.interface=&st->ops;
	284	st->ops.st=st;
	285	st->ops.request_notify=request_notify;
	286	st->ops.release_notify=release_notify;
	287	st->ops.sendmsg=udp_sendmsg;
5edf478f	288	st->ops.addr_to_string=addr_to_string;
ff05a229	289	st->use_proxy=False;
2fe58dfd SE	290
	291	i=list_elem(args,0);
	292	if (!i \|\| i->type!=t_dict) {
	293	cfgfatal(st->loc,"udp","first argument must be a dictionary\n");
	294	}
	295	d=i->data.dict;
	296
a32d56fb	297	st->addr.sa.sa_family=AF_INET;
3b83c932	298	j=dict_find_item(d,"address",False,"udp",st->loc);
a32d56fb IJ	299	st->addr.sin.sin_addr.s_addr=j?string_item_to_ipaddr(j, "udp"):INADDR_ANY;
a32d56fb IJ	300	st->addr.sin.sin_port=dict_read_number(d,"port",True,"udp",st->loc,0);
2fe58dfd	301	st->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,"udp",st->loc);
b2a56f7c	302	st->authbind=dict_read_string(d,"authbind",False,"udp",st->loc);
ff05a229 SE	303	l=dict_lookup(d,"proxy");
	304	if (l) {
	305	st->use_proxy=True;
a32d56fb	306	st->proxy.sa.sa_family=AF_INET;
ff05a229 SE	307	i=list_elem(l,0);
	308	if (!i \|\| i->type!=t_string) {
	309	cfgfatal(st->loc,"udp","proxy must supply ""addr"",port\n");
	310	}
	311	a=string_item_to_ipaddr(i,"proxy");
a32d56fb	312	st->proxy.sin.sin_addr.s_addr=htonl(a);
ff05a229 SE	313	i=list_elem(l,1);
	314	if (!i \|\| i->type!=t_number) {
	315	cfgfatal(st->loc,"udp","proxy must supply ""addr"",port\n");
	316	}
a32d56fb	317	st->proxy.sin.sin_port=htons(i->data.number);
ff05a229	318	}
2fe58dfd	319
3abd18e8 IJ	320	update_max_start_pad(&comm_max_start_pad, st->use_proxy ? 8 : 0);
3abd18e8 IJ	321
baa06aeb	322	add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
2fe58dfd SE	323
	324	return new_closure(&st->cl);
	325	}
	326
2fe58dfd SE	327	void udp_module(dict_t *dict)
	328	{
	329	add_closure(dict,"udp",udp_apply);
	330	}