chiark / gitweb /
site: dynamically create and destroy transform instances
[secnet.git] / udp.c
diff --git a/udp.c b/udp.c
index 7ff4d5f..483ed37 100644 (file)
--- a/udp.c
+++ b/udp.c
 #include <errno.h>
 #include <sys/socket.h>
 #include <sys/wait.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
 #include "util.h"
 #include "unaligned.h"
 #include "ipaddr.h"
+#include "magic.h"
 
 static beforepoll_fn udp_beforepoll;
 static afterpoll_fn udp_afterpoll;
@@ -46,6 +49,30 @@ struct udp {
     struct sockaddr_in proxy;
 };
 
+static const char *saddr_to_string(const struct sockaddr_in *sin) {
+    static char bufs[2][100];
+    static int b;
+
+    b ^= 1;
+    snprintf(bufs[b], sizeof(bufs[b]), "[%s]:%d",
+            inet_ntoa(sin->sin_addr),
+            ntohs(sin->sin_port));
+    return bufs[b];
+}
+
+static const char *addr_to_string(void *commst, const struct comm_addr *ca) {
+    struct udp *st=commst;
+    static char sbuf[100];
+
+    struct sockaddr_in la;
+    la.sin_addr.s_addr=htonl(st->addr);
+    la.sin_port=htons(st->port);
+
+    snprintf(sbuf, sizeof(sbuf), "udp:%s-%s",
+            saddr_to_string(&la), saddr_to_string(&ca->sin));
+    return sbuf;
+}
+
 static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
                          int *timeout_io)
 {
@@ -71,6 +98,7 @@ static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
 
     if (nfds && (fds->revents & POLLIN)) {
        do {
+           FILLZERO(from);
            fromlen=sizeof(from);
            BUF_ASSERT_FREE(st->rbuf);
            BUF_ALLOC(st->rbuf,"udp_afterpoll");
@@ -93,25 +121,28 @@ static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
                    buf_unprepend(st->rbuf,2);
                    memcpy(&from.sin_port,buf_unprepend(st->rbuf,2),2);
                }
+               struct comm_addr ca;
+               FILLZERO(ca);
+               ca.comm=&st->ops;
+               ca.sin=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) {
-                   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));
+                   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);
@@ -156,21 +187,21 @@ static void release_notify(void *commst, void *nst, comm_notify_fn *fn)
 }
 
 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;
 
     if (st->use_proxy) {
        sa=buf->start-8;
-       memcpy(sa,&dest->sin_addr,4);
+       memcpy(sa,&dest->sin.sin_addr,4);
        memset(sa+4,0,4);
-       memcpy(sa+6,&dest->sin_port,2);
+       memcpy(sa+6,&dest->sin.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));
+              (struct sockaddr *)&dest->sin, sizeof(dest->sin));
     }
 
     return True;
@@ -194,7 +225,7 @@ static void udp_phase_hook(void *sst, uint32_t new_phase)
                     st->loc.file,st->loc.line);
     }
 
-    memset(&addr, 0, sizeof(addr));
+    FILLZERO(addr);
     addr.sin_family=AF_INET;
     addr.sin_addr.s_addr=htonl(st->addr);
     addr.sin_port=htons(st->port);
@@ -210,8 +241,8 @@ static void udp_phase_hook(void *sst, uint32_t new_phase)
        }
        if (c==0) {
            char *argv[4], addrstr[9], portstr[5];
-           sprintf(addrstr,"%08lX",(long)st->addr);
-           sprintf(portstr,"%04X",st->port);
+           sprintf(addrstr,"%08lX",(long)addr.sin_addr.s_addr);
+           sprintf(portstr,"%04X",addr.sin_port);
            argv[0]=st->authbind;
            argv[1]=addrstr;
            argv[2]=portstr;
@@ -262,6 +293,7 @@ static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
     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->port=0;
     st->use_proxy=False;
 
@@ -279,7 +311,7 @@ static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
     l=dict_lookup(d,"proxy");
     if (l) {
        st->use_proxy=True;
-       memset(&st->proxy,0,sizeof(st->proxy));
+       FILLZERO(st->proxy);
        st->proxy.sin_family=AF_INET;
        i=list_elem(l,0);
        if (!i || i->type!=t_string) {