Add nng_str_sockaddr to get string representation of socket address.

include/nng/nng.h

@@ -250,6 +250,11 @@ NNG_DECL int nng_socket_get_ptr(nng_socket, const char *, void **);
 NNG_DECL int nng_socket_get_ms(nng_socket, const char *, nng_duration *);
 NNG_DECL int nng_socket_get_addr(nng_socket, const char *, nng_sockaddr *);
 
+// Utility function for getting a printable form of the socket address
+// for display in logs, etc.  It is not intended to be parsed, and the
+// display format may change without notice.
+NNG_DECL const char *nng_str_sockaddr(const nng_sockaddr *sa, char *buf, size_t bufsz);
+
 // Arguably the pipe callback functions could be handled as an option,
 // but with the need to specify an argument, we find it best to unify
 // this as a separate function to pass in the argument and the callback.

src/core/CMakeLists.txt

@@ -57,6 +57,7 @@ nng_sources(
         protocol.h
         reap.c
         reap.h
+        sockaddr.c
         socket.c
         socket.h
         sockimpl.h

src/core/sockaddr.c

@@ -0,0 +1,158 @@
+//
+// Copyright 2024 Staysail Systems, Inc. <info@staysail.tech>
+//
+// This software is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+#include "core/nng_impl.h"
+#include "nng/nng.h"
+
+#include <stdio.h>
+#include <string.h>
+
+static const char *
+str_sa_inproc(const nng_sockaddr_inproc *sa, char *buf, size_t bufsz)
+{
+	snprintf(buf, bufsz, "inproc{%s}", sa->sa_name);
+	return buf;
+}
+
+static const char *
+str_sa_inet(const nng_sockaddr_in *sa, char *buf, size_t bufsz)
+{
+	uint8_t *a_bytes = (uint8_t *) &sa->sa_addr;
+	uint8_t *p_bytes = (uint8_t *) &sa->sa_port;
+
+	snprintf(buf, bufsz, "inet{%u.%u.%u.%u:%u}", a_bytes[0], a_bytes[1],
+	    a_bytes[2], a_bytes[3],
+	    (((uint16_t) p_bytes[0]) << 8) + p_bytes[1]);
+	return (buf);
+}
+
+// emit an IPv6 address in "short form"
+static char *
+nni_inet_ntop(const uint8_t addr[16], char buf[46])
+{
+
+	const uint8_t v4map[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 0xff,
+		0xff };
+
+	if (memcmp(addr, v4map, 12) == 0) {
+		snprintf(buf, 46, "::ffff:%u.%u.%u.%u", addr[12], addr[13],
+		    addr[14], addr[15]);
+		return (buf);
+	}
+
+	uint8_t off    = 0; // offset of first set of elided zeros
+	uint8_t cnt    = 0; // how many elided zeros so far
+	uint8_t maxoff = 0; // offset of largest compressed region
+	uint8_t maxcnt = 0; // how many elided zeros at maxoff
+
+	// look for the largest compressible region
+	for (uint8_t i = 0; i < 16; i += 2) {
+		// is this word zero?
+		if ((addr[i] == 0) && (addr[i + 1] == 0)) {
+			cnt += 2;
+			// if this was the first zero word in region, record it
+			if (cnt == 2) {
+				off = i;
+			}
+			// possibly update the maximums
+			if (cnt > maxcnt) {
+				maxcnt = cnt;
+				maxoff = off;
+			}
+		} else {
+			cnt = 0;
+		}
+	}
+	if (maxcnt < 2) {
+		maxoff = 0xff; // too big for anything
+	}
+
+	int   idx = 0;
+	char *sep = "";
+	for (uint8_t i = 0; i < 16; i += 2) {
+		if (i == maxoff) {
+			buf[idx++] = ':';
+			buf[idx++] = ':';
+			buf[idx]   = 0;
+			sep        = "";
+		} else if (i < maxoff || i >= maxoff + maxcnt) {
+			idx += snprintf(buf + idx, 46 - idx, "%s%x", sep,
+			    (((uint16_t) addr[i]) << 8) + addr[i + 1]);
+			buf[idx] = 0;
+			sep      = ":";
+		}
+	}
+	return (buf);
+}
+
+static const char *
+str_sa_inet6(const nng_sockaddr_in6 *sa, char *buf, size_t bufsz)
+{
+	const uint8_t *p_bytes = (uint8_t *) &sa->sa_port;
+	char           istr[46];
+
+	if (sa->sa_scope) {
+		snprintf(buf, bufsz, "inet6{[%s]:%u%%%u}",
+		    nni_inet_ntop(sa->sa_addr, istr),
+		    (((uint16_t) (p_bytes[0])) << 8) + p_bytes[1],
+		    sa->sa_scope);
+	} else {
+		snprintf(buf, bufsz, "inet6{[%s]:%u}",
+		    nni_inet_ntop(sa->sa_addr, istr),
+		    (((uint16_t) (p_bytes[0])) << 8) + p_bytes[1]);
+	}
+	return (buf);
+}
+
+static const char *
+str_sa_ipc(const nng_sockaddr_ipc *sa, char *buf, size_t bufsz)
+{
+	// does not deal well with embedded "{}" chars
+	snprintf(buf, bufsz, "ipc{%s}", sa->sa_path);
+	return (buf);
+}
+
+static const char *
+str_sa_abstract(const nng_sockaddr_abstract *sa, char *buf, size_t bufsz)
+{
+	// does not deal well with embedded "{}" chars
+	snprintf(buf, bufsz, "abstract{%s}", sa->sa_name);
+	return (buf);
+}
+
+static const char *
+str_sa_zt(const nng_sockaddr_zt *sa, char *buf, size_t bufsz)
+{
+	snprintf(buf, bufsz, "zt{%llx,%llx,%u}",
+	    (unsigned long long) sa->sa_nodeid,
+	    (unsigned long long) sa->sa_nwid, sa->sa_port);
+	return (buf);
+}
+
+const char *
+nng_str_sockaddr(const nng_sockaddr *sa, char *buf, size_t bufsz)
+{
+	switch (sa->s_family) {
+	case NNG_AF_INPROC:
+		return (str_sa_inproc(&sa->s_inproc, buf, bufsz));
+	case NNG_AF_INET:
+		return (str_sa_inet(&sa->s_in, buf, bufsz));
+	case NNG_AF_INET6:
+		return (str_sa_inet6(&sa->s_in6, buf, bufsz));
+	case NNG_AF_IPC:
+		return (str_sa_ipc(&sa->s_ipc, buf, bufsz));
+	case NNG_AF_ABSTRACT:
+		return (str_sa_abstract(&sa->s_abstract, buf, bufsz));
+	case NNG_AF_ZT:
+	    return (str_sa_zt(&sa->s_zt, buf, bufsz));
+	case NNG_AF_UNSPEC:
+	default:
+		return ("unknown{}");
+	}
+}