Import release 0.1.11

[secnet.git] / udp.c

diff --git a/udp.c b/udp.c
index ba9f9d6fe5f0cb095089c37f667aa53c4cc6631b..65208650f998a7cbc5f670a1d7114ae40adc677b 100644 (file)
--- a/udp.c
+++ b/udp.c
@@ -19,7 +19,9 @@
 #include <string.h>
 #include <errno.h>
 #include <sys/socket.h>
+#include <sys/wait.h>
 #include "util.h"
+#include "unaligned.h"
 
 static beforepoll_fn udp_beforepoll;
 static afterpoll_fn udp_afterpoll;
@@ -43,6 +45,7 @@ struct udp {
     struct cloc loc;
     uint16_t port;
     int fd;
+    string_t authbind;
     struct buffer_if *rbuf;
     struct notify_list *notify;
 };
@@ -89,8 +92,17 @@ static void udp_afterpoll(void *state, struct pollfd *fds, int nfds,
                    }
                }
                if (!done) {
+                   uint32_t source,dest;
                    /* XXX manufacture and send NAK packet */
-                   Message(M_WARNING,"Need to send NAK\n");
+                   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);
@@ -167,8 +179,37 @@ static void udp_phase_hook(void *sst, uint32_t new_phase)
     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]="00000000";
+           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");
@@ -201,6 +242,7 @@ static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
 
     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);
 
     add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);