bgpd convert rtr_proto.c to new ibuf API

[Claudio Jeker]

More ibuf cleanup. rtr_proto.c still uses ibuf_add() where it could use
the new functions.

Two bits I'm unsure about:
- I had to change some sizeof() to use native types (I especially dislike
  the sizeof(struct rtr_header).
- ibuf_add_nXX() can fail if the value is too large. Which should be
  impossible but still maybe it would be better to check for errors.

-- 
:wq Claudio

Index: rtr_proto.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/rtr_proto.c,v
retrieving revision 1.17
diff -u -p -r1.17 rtr_proto.c
--- rtr_proto.c 16 Aug 2023 08:26:35 -0000      1.17
+++ rtr_proto.c 19 Oct 2023 08:35:49 -0000
@@ -233,24 +233,21 @@ rtr_newmsg(struct rtr_session *rs, enum 
     uint16_t session_id)
 {
        struct ibuf *buf;
-       struct rtr_header rh;
 
        if (len > RTR_MAX_LEN) {
                errno = ERANGE;
                return NULL;
        }
-       len += sizeof(rh);
+       len += sizeof(struct rtr_header);
        if ((buf = ibuf_open(len)) == NULL)
                return NULL;
 
-       memset(&rh, 0, sizeof(rh));
-       rh.version = rs->version;
-       rh.type = type;
-       rh.session_id = htons(session_id);
-       rh.length = htonl(len);
-
        /* cannot fail with fixed buffers */
-       ibuf_add(buf, &rh, sizeof(rh));
+       ibuf_add_n8(buf, rs->version);
+       ibuf_add_n8(buf, type);
+       ibuf_add_n16(buf, session_id);
+       ibuf_add_n32(buf, len);
+
        return buf;
 }
 
@@ -264,7 +261,6 @@ rtr_send_error(struct rtr_session *rs, e
 {
        struct ibuf *buf;
        size_t mlen = 0;
-       uint32_t hdrlen;
 
        rs->last_sent_error = err;
        if (msg) {
@@ -273,7 +269,7 @@ rtr_send_error(struct rtr_session *rs, e
        } else
                memset(rs->last_sent_msg, 0, sizeof(rs->last_sent_msg));
 
-       buf = rtr_newmsg(rs, ERROR_REPORT, 2 * sizeof(hdrlen) + len + mlen,
+       buf = rtr_newmsg(rs, ERROR_REPORT, 2 * sizeof(uint32_t) + len + mlen,
            err);
        if (buf == NULL) {
                log_warn("rtr %s: send error report", log_rtr(rs));
@@ -281,11 +277,9 @@ rtr_send_error(struct rtr_session *rs, e
        }
 
        /* cannot fail with fixed buffers */
-       hdrlen = ntohl(len);
-       ibuf_add(buf, &hdrlen, sizeof(hdrlen));
+       ibuf_add_n32(buf, len);
        ibuf_add(buf, pdu, len);
-       hdrlen = ntohl(mlen);
-       ibuf_add(buf, &hdrlen, sizeof(hdrlen));
+       ibuf_add_n32(buf, mlen);
        ibuf_add(buf, msg, mlen);
        ibuf_close(&rs->w, buf);
 
@@ -313,9 +307,8 @@ static void
 rtr_send_serial_query(struct rtr_session *rs)
 {
        struct ibuf *buf;
-       uint32_t s;
 
-       buf = rtr_newmsg(rs, SERIAL_QUERY, sizeof(s), rs->session_id);
+       buf = rtr_newmsg(rs, SERIAL_QUERY, sizeof(uint32_t), rs->session_id);
        if (buf == NULL) {
                log_warn("rtr %s: send serial query", log_rtr(rs));
                rtr_send_error(rs, INTERNAL_ERROR, "out of memory", NULL, 0);
@@ -323,8 +316,7 @@ rtr_send_serial_query(struct rtr_session
        }
 
        /* cannot fail with fixed buffers */
-       s = htonl(rs->serial);
-       ibuf_add(buf, &s, sizeof(s));
+       ibuf_add_n32(buf, rs->serial);
        ibuf_close(&rs->w, buf);
 }