X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=udp.c;h=307a67a9f7d67cdb8dd42758040d3435e054d070;hb=7138d0c54cd2212439434d27cb2d6ea775c3039b;hp=177ce1c23b4481563cf3d2e2895dcb780ae8cc45;hpb=2fe58dfd10216a37f1ece081f926971882de112e;p=secnet.git

diff --git a/udp.c b/udp.c
index 177ce1c..307a67a 100644
--- a/udp.c
+++ b/udp.c
@@ -12,16 +12,14 @@
  * 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 <netinet/in.h>
-
-#include "secnet.h"
+#include <sys/wait.h>
 #include "util.h"
 
 static beforepoll_fn udp_beforepoll;
@@ -44,7 +42,9 @@ struct udp {
     closure_t cl;
     struct comm_if ops;
     struct cloc loc;
+    uint16_t port;
     int fd;
+    string_t authbind;
     struct buffer_if *rbuf;
     struct notify_list *notify;
 };
@@ -148,14 +148,69 @@ static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
     return True;
 }
 
+static void udp_phase_hook(void *sst, uint32_t new_phase)
+{
+    struct udp *st=sst;
+    struct sockaddr_in addr;
+
+    st->fd=socket(AF_INET, SOCK_DGRAM, 0);
+    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);
+    }
+    if (fcntl(st->fd, F_SETFD, FD_CLOEXEC)==-1) {
+	fatal_perror("udp (%s:%d): fcntl(set FD_CLOEXEC)",
+		     st->loc.file,st->loc.line);
+    }
+
+    memset(&addr, 0, sizeof(addr));
+    addr.sin_family=AF_INET;
+    addr.sin_port=htons(st->port);
+    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");
+}
+
 static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
 			 list_t *args)
 {
     struct udp *st;
     item_t *i;
     dict_t *d;
-    uint16_t local_port=0;
-    struct sockaddr_in addr;
 
     st=safe_malloc(sizeof(*st),"udp_apply(st)");
     st->loc=loc;
@@ -167,6 +222,7 @@ 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->port=0;
 
     i=list_elem(args,0);
     if (!i || i->type!=t_dict) {
@@ -174,32 +230,11 @@ static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
     }
     d=i->data.dict;
 
-    local_port=dict_read_number(d,"port",False,"udp",st->loc,0);
+    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);
 
-    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);
-    }
-
-    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);
-    }
-
-    register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp");
+    add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
 
     return new_closure(&st->cl);
 }