PEER_LIMITS: modernize to sa46 and add notification cb

There are a bunch of sa46-aware lws apis for formatting, etc sa46
in ./include/libwebsockets/lws-network-helper.h

include/libwebsockets/lws-context-vhost.h

@@ -237,6 +237,10 @@ struct lws_ss_plugin;
 
 typedef int (*lws_context_ready_cb_t)(struct lws_context *context);
 
+typedef int (*lws_peer_limits_notify_t)(struct lws_context *ctx,
+					lws_sockfd_type sockfd,
+					lws_sockaddr46 *sa46);
+
 /** struct lws_context_creation_info - parameters to create context and /or vhost with
  *
  * This is also used to create vhosts.... if LWS_SERVER_OPTION_EXPLICIT_VHOSTS
@@ -738,6 +742,15 @@ struct lws_context_creation_info {
 	/**< 0 = inherit the initial ulimit for files / sockets from the startup
 	 * environment.  Nonzero = try to set the limit for this process.
 	 */
+#if defined(LWS_WITH_PEER_LIMITS)
+	lws_peer_limits_notify_t pl_notify_cb;
+	/**< CONTEXT: NULL, or a callback to receive notifications each time a
+	 * connection is being dropped because of peer limits.
+	 *
+	 * The callback provides the context, and an lws_sockaddr46 with the
+	 * peer address and port.
+	 */
+#endif
 
 	/* Add new things just above here ---^
 	 * This is part of the ABI, don't needlessly break compatibility

lib/core-net/adopt.c

@@ -338,11 +338,16 @@ lws_adopt_descriptor_vhost_via_info(const lws_adopt_desc_t *info)
 
 		if (peer && info->vh->context->ip_limit_wsi &&
 		    peer->count_wsi >= info->vh->context->ip_limit_wsi) {
-			lwsl_notice("Peer reached wsi limit %d\n",
+			lwsl_info("Peer reached wsi limit %d\n",
 					info->vh->context->ip_limit_wsi);
 			lws_stats_bump(&info->vh->context->pt[0],
 					      LWSSTATS_C_PEER_LIMIT_WSI_DENIED,
 					      1);
+			if (info->vh->context->pl_notify_cb)
+				info->vh->context->pl_notify_cb(
+							info->vh->context,
+							info->fd.sockfd,
+							&peer->sa46);
 			compatible_close(info->fd.sockfd);
 			return NULL;
 		}

lib/core-net/private-lib-core-net.h

@@ -187,10 +187,11 @@ struct lws_peer {
 	struct lws_peer *next;
 	struct lws_peer *peer_wait_list;
 
+	lws_sockaddr46	sa46;
+
 	time_t time_created;
 	time_t time_closed_all;
 
-	uint8_t addr[32];
 	uint32_t hash;
 	uint32_t count_wsi;
 	uint32_t total_wsi;
@@ -198,8 +199,6 @@ struct lws_peer {
 #if defined(LWS_ROLE_H1) || defined(LWS_ROLE_H2)
 	struct lws_peer_role_http http;
 #endif
-
-	uint8_t af;
 };
 #endif
 

lib/core/context.c

@@ -661,6 +661,7 @@ lws_create_context(const struct lws_context_creation_info *info)
 
 	context->ip_limit_ah = info->ip_limit_ah;
 	context->ip_limit_wsi = info->ip_limit_wsi;
+	context->pl_notify_cb = info->pl_notify_cb;
 #endif
 
 	lwsl_info(" mem: context:         %5lu B (%ld ctx + (%ld thr x %d))\n",

lib/core/private-lib-core.h

@@ -432,9 +432,10 @@ struct lws_context {
 #endif
 
 #if defined(LWS_WITH_PEER_LIMITS)
-	struct lws_peer **pl_hash_table;
-	struct lws_peer *peer_wait_list;
-	time_t next_cull;
+	struct lws_peer			**pl_hash_table;
+	struct lws_peer			*peer_wait_list;
+	lws_peer_limits_notify_t	pl_notify_cb;
+	time_t				next_cull;
 #endif
 
 	const lws_system_ops_t *system_ops;

lib/misc/peer-limits.c

@@ -1,7 +1,7 @@
 /*
  * libwebsockets - small server side websockets and web server implementation
  *
- * Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
+ * Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to
@@ -60,42 +60,32 @@ struct lws_peer *
 lws_get_or_create_peer(struct lws_vhost *vhost, lws_sockfd_type sockfd)
 {
 	struct lws_context *context = vhost->context;
-	socklen_t rlen = 0;
-	void *q;
-	uint8_t *q8;
 	struct lws_peer *peer;
+	lws_sockaddr46 sa46;
+	socklen_t rlen = 0;
 	uint32_t hash = 0;
-	int n, af = AF_INET;
-	struct sockaddr_storage addr;
+	uint8_t *q8;
+	void *q;
+	int n;
 
 	if (vhost->options & LWS_SERVER_OPTION_UNIX_SOCK)
 		return NULL;
 
-#ifdef LWS_WITH_IPV6
-	if (LWS_IPV6_ENABLED(vhost)) {
-		af = AF_INET6;
-	}
-#endif
-	rlen = sizeof(addr);
-	if (getpeername(sockfd, (struct sockaddr*)&addr, &rlen))
+	rlen = sizeof(sa46);
+	if (getpeername(sockfd, (struct sockaddr*)&sa46, &rlen))
 		/* eg, udp doesn't have to have a peer */
 		return NULL;
 
 #ifdef LWS_WITH_IPV6
-	if (af == AF_INET)
+	if (sa46.sa4.sin_family == AF_INET6) {
+		q = &sa46.sa6.sin6_addr;
+		rlen = sizeof(sa46.sa6.sin6_addr);
+	} else
 #endif
 	{
-		struct sockaddr_in *s = (struct sockaddr_in *)&addr;
-		q = &s->sin_addr;
-		rlen = sizeof(s->sin_addr);
+		q = &sa46.sa4.sin_addr;
+		rlen = sizeof(sa46.sa4.sin_addr);
 	}
-#ifdef LWS_WITH_IPV6
-	else {
-		struct sockaddr_in6 *s = (struct sockaddr_in6 *)&addr;
-		q = &s->sin6_addr;
-		rlen = sizeof(s->sin6_addr);
-	}
-#endif
 
 	q8 = q;
 	for (n = 0; n < (int)rlen; n++)
@@ -107,9 +97,21 @@ lws_get_or_create_peer(struct lws_vhost *vhost, lws_sockfd_type sockfd)
 
 	lws_start_foreach_ll(struct lws_peer *, peerx,
 			     context->pl_hash_table[hash]) {
-		if (peerx->af == af && !memcmp(q, peerx->addr, rlen)) {
-			lws_context_unlock(context); /* === */
-			return peerx;
+		if (peerx->sa46.sa4.sin_family == sa46.sa4.sin_family) {
+#if defined(LWS_WITH_IPV6)
+			if (sa46.sa4.sin_family == AF_INET6 &&
+			    !memcmp(q, &peerx->sa46.sa6.sin6_addr, rlen))
+				goto hit;
+#endif
+			if (sa46.sa4.sin_family == AF_INET &&
+			    !memcmp(q, &peerx->sa46.sa4.sin_addr, rlen)) {
+#if defined(LWS_WITH_IPV6)
+hit:
+#endif
+				lws_context_unlock(context); /* === */
+
+				return peerx;
+			}
 		}
 	} lws_end_foreach_ll(peerx, next);
 
@@ -125,9 +127,8 @@ lws_get_or_create_peer(struct lws_vhost *vhost, lws_sockfd_type sockfd)
 	context->count_peers++;
 	peer->next = context->pl_hash_table[hash];
 	peer->hash = hash;
-	peer->af = af;
+	peer->sa46 = sa46;
 	context->pl_hash_table[hash] = peer;
-	memcpy(peer->addr, q, rlen);
 	time(&peer->time_created);
 	/*
 	 * On creation, the peer has no wsi attached, so is created on the