[PATCH 22/41] udp, util: Break out send_nak function

[Ian Jackson]

Move the code in udp.c which constructs NAKs into its own function
in util.c.  This will make it easier to reuse.

Signed-off-by: Ian Jackson <ijackson at chiark.greenend.org.uk>
---
 udp.c  |   20 +++++---------------
 util.c |   17 +++++++++++++++++
 util.h |    4 ++++
 3 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/udp.c b/udp.c
index c83e618..483ed37 100644
--- a/udp.c
+++ b/udp.c
@@ -121,12 +121,12 @@ 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) {
-		    struct comm_addr ca;
-		    FILLZERO(ca);
-		    ca.comm=&st->ops;
-		    ca.sin=from;
 		    if (n->fn(n->state, st->rbuf, &ca)) {
 			done=True;
 			break;
@@ -141,17 +141,7 @@ static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
 			/* 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, peer %s):"
-				" %08"PRIx32"<-%08"PRIx32": %08"PRIx32":"
-				" unwanted/incorrect, sending NAK\n",
-				st->port, saddr_to_string(&from),
-				dest, source, msgtype);
-			buffer_init(st->rbuf,0);
-			buf_append_uint32(st->rbuf,dest);
-			buf_append_uint32(st->rbuf,source);
-			buf_append_uint32(st->rbuf,LABEL_NAK);
-			sendto(st->fd, st->rbuf->start, st->rbuf->size, 0,
-			       (struct sockaddr *)&from, sizeof(from));
+			send_nak(&ca,source,dest,msgtype,st->rbuf,"unwanted");
 		    }
 		    BUF_FREE(st->rbuf);
 		}
diff --git a/util.c b/util.c
index 3d11987..1b46bc0 100644
--- a/util.c
+++ b/util.c
@@ -38,6 +38,7 @@
 #include <sys/wait.h>
 #include "util.h"
 #include "unaligned.h"
+#include "magic.h"
 
 #define MIN_BUFFER_SIZE 64
 #define DEFAULT_BUFFER_SIZE 4096
@@ -381,6 +382,22 @@ static list_t *buffer_apply(closure_t *self, struct cloc loc, dict_t *context,
     return new_closure(&st->cl);
 }
 
+void send_nak(const struct comm_addr *dest, uint32_t our_index,
+	      uint32_t their_index, uint32_t msgtype,
+	      struct buffer_if *buf, const char *logwhy)
+{
+    buffer_init(buf,dest->comm->min_start_pad);
+    buf_append_uint32(buf,their_index);
+    buf_append_uint32(buf,our_index);
+    buf_append_uint32(buf,LABEL_NAK);
+    if (logwhy)
+	Message(M_INFO,"%s: %08"PRIx32"<-%08"PRIx32": %08"PRIx32":"
+		" %s; sending NAK\n",
+		dest->comm->addr_to_string(dest->comm->st,dest),
+		our_index, their_index, msgtype, logwhy);
+    dest->comm->sendmsg(dest->comm->st, buf, dest);
+}
+
 int consttime_memeq(const void *s1in, const void *s2in, size_t n)
 {
     const uint8_t *s1=s1in, *s2=s2in;
diff --git a/util.h b/util.h
index cbe9f52..816c056 100644
--- a/util.h
+++ b/util.h
@@ -45,6 +45,10 @@ extern int32_t write_mpbin(MP_INT *a, uint8_t *buffer, int32_t buflen);
 
 extern struct log_if *init_log(list_t *loglist);
 
+extern void send_nak(const struct comm_addr *dest, uint32_t our_index,
+		     uint32_t their_index, uint32_t msgtype,
+		     struct buffer_if *buf, const char *logwhy);
+
 extern int consttime_memeq(const void *s1, const void *s2, size_t n);
 
 #endif /* util_h */
-- 
1.7.2.5