iked: ibuf saga step 2

[Claudio Jeker]

Kill ibuf_prepend() it is used only once and the function does unholy
things to the ibuf passed in. Just do the obivous dance in the callee.
The only thing to be careful about is the fact that all pointers of buf
are replaced (msg->msg_data).

Tested with iked -t (which should use this codepath).
-- 
:wq Claudio

Index: iked.h
===================================================================
RCS file: /cvs/src/sbin/iked/iked.h,v
retrieving revision 1.213
diff -u -p -r1.213 iked.h
--- iked.h      23 May 2023 13:57:14 -0000      1.213
+++ iked.h      26 May 2023 07:21:43 -0000
@@ -1279,7 +1279,6 @@ struct ibuf *
         ibuf_dup(struct ibuf *);
 struct ibuf *
         ibuf_random(size_t);
-int     ibuf_prepend(struct ibuf *, void *, size_t);
 int     ibuf_strcat(struct ibuf **, const char *);
 int     ibuf_strlen(struct ibuf *);
 
Index: ikev2_msg.c
===================================================================
RCS file: /cvs/src/sbin/iked/ikev2_msg.c,v
retrieving revision 1.92
diff -u -p -r1.92 ikev2_msg.c
--- ikev2_msg.c 23 May 2023 13:57:14 -0000      1.92
+++ ikev2_msg.c 26 May 2023 07:20:13 -0000
@@ -290,10 +290,17 @@ ikev2_msg_send(struct iked *env, struct 
            ibuf_length(buf), isnatt ? ", NAT-T" : "");
 
        if (isnatt) {
-               if (ibuf_prepend(buf, &natt, sizeof(natt)) == -1) {
+               struct ibuf *new;
+               if ((new = ibuf_new(&natt, sizeof(natt))) == NULL) {
                        log_debug("%s: failed to set NAT-T", __func__);
                        return (-1);
                }
+               if (ibuf_cat(new, buf) == -1) {
+                       log_debug("%s: failed to set NAT-T", __func__);
+                       return (-1);
+               }
+               ibuf_free(buf);
+               buf = msg->msg_data = new;
        }
 
        if (sendtofrom(msg->msg_fd, ibuf_data(buf), ibuf_size(buf), 0,
Index: imsg_util.c
===================================================================
RCS file: /cvs/src/sbin/iked/imsg_util.c,v
retrieving revision 1.16
diff -u -p -r1.16 imsg_util.c
--- imsg_util.c 23 May 2023 13:57:14 -0000      1.16
+++ imsg_util.c 26 May 2023 07:21:26 -0000
@@ -146,25 +146,6 @@ ibuf_setsize(struct ibuf *buf, size_t le
 }
 
 int
-ibuf_prepend(struct ibuf *buf, void *data, size_t len)
-{
-       struct ibuf     *new;
-
-       /* Swap buffers (we could also use memmove here) */
-       if ((new = ibuf_new(data, len)) == NULL)
-               return (-1);
-       if (ibuf_cat(new, buf) == -1) {
-               ibuf_free(new);
-               return (-1);
-       }
-       free(buf->buf);
-       memcpy(buf, new, sizeof(*buf));
-       free(new);
-
-       return (0);
-}
-
-int
 ibuf_strcat(struct ibuf **buf, const char *s)
 {
        size_t slen;