autofs-5.0.3 - eliminate redundant DNS name lookups

From: Ian Kent <raven@themaw.net>

When autofs tries to lookup a DNS host name where one or more DNS
servers aren't available the mount can take a long time. This is
caused by autofs doing the name lookups more often than it needs
to. This patch removes a number of these redundant name lookups.
---

 CHANGELOG            |    1 +
 include/replicated.h |    1 +
 include/rpc_subs.h   |    4 +++-
 lib/rpc_subs.c       |   22 ++++++++++++++++++++--
 modules/replicated.c |   25 +++++++++++++++++++------
 5 files changed, 44 insertions(+), 9 deletions(-)


diff --git a/CHANGELOG b/CHANGELOG
index 3ed84d3..995daea 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -17,6 +17,7 @@
 - add check for exports automatically mounted by NFS kernel client.
 - update nsswitch parser to ignore nsswitch sources that aren't supported.
 - check for map key in (possible) alternate map sources when doing lookup.
+- eliminate redundant DNS name lookups.
  
 14/01/2008 autofs-5.0.3
 -----------------------
diff --git a/include/replicated.h b/include/replicated.h
index 672f853..88cd08a 100644
--- a/include/replicated.h
+++ b/include/replicated.h
@@ -52,6 +52,7 @@
 struct host {
 	char *name;
 	char *addr;
+	size_t addr_len;
 	char *path;
 	unsigned int version;
 	unsigned int proximity;
diff --git a/include/rpc_subs.h b/include/rpc_subs.h
index 3292e01..e20a89d 100644
--- a/include/rpc_subs.h
+++ b/include/rpc_subs.h
@@ -46,6 +46,8 @@
 
 struct conn_info {
 	const char *host;
+	const char *addr;
+	size_t addr_len;
 	unsigned short port;
 	unsigned long program;
 	unsigned long version;
@@ -61,7 +63,7 @@ int rpc_udp_getclient(struct conn_info *, unsigned int, unsigned int);
 void rpc_destroy_udp_client(struct conn_info *);
 int rpc_tcp_getclient(struct conn_info *, unsigned int, unsigned int);
 void rpc_destroy_tcp_client(struct conn_info *);
-int rpc_portmap_getclient(struct conn_info *, const char *, const char *, unsigned int);
+int rpc_portmap_getclient(struct conn_info *, const char *, const char *, size_t, const char *, unsigned int);
 unsigned short rpc_portmap_getport(struct conn_info *, struct pmap *);
 int rpc_ping_proto(struct conn_info *);
 int rpc_ping(const char *, long, long, unsigned int);
diff --git a/lib/rpc_subs.c b/lib/rpc_subs.c
index 5797639..6be86c6 100644
--- a/lib/rpc_subs.c
+++ b/lib/rpc_subs.c
@@ -86,6 +86,11 @@ static CLIENT *create_udp_client(struct conn_info *info)
 	memset(&raddr, 0, sizeof(raddr));
 
 	raddr.sin_family = AF_INET;
+	if (info->addr) {
+		memcpy(&raddr.sin_addr.s_addr, info->addr, info->addr_len);
+		goto got_addr;
+	}
+
 	if (inet_aton(info->host, &raddr.sin_addr))
 		goto got_addr;
 
@@ -295,6 +300,11 @@ static CLIENT *create_tcp_client(struct conn_info *info)
 	memset(&addr, 0, sizeof(addr));
 
 	addr.sin_family = AF_INET;
+	if (info->addr) {
+		memcpy(&addr.sin_addr.s_addr, info->addr, info->addr_len);
+		goto got_addr;
+	}
+
 	if (inet_aton(info->host, &addr.sin_addr))
 		goto got_addr;
 
@@ -407,8 +417,8 @@ void rpc_destroy_tcp_client(struct conn_info *info)
 }
 
 int rpc_portmap_getclient(struct conn_info *info,
-			  const char *host, const char *proto,
-			  unsigned int option)
+			  const char *host, const char *addr, size_t addr_len,
+			  const char *proto, unsigned int option)
 {
 	struct protoent *pe_proto;
 	CLIENT *client;
@@ -418,6 +428,8 @@ int rpc_portmap_getclient(struct conn_info *info,
 		return 0;
 
 	info->host = host;
+	info->addr = addr;
+	info->addr_len = addr_len;
 	info->program = PMAPPROG;
 	info->port = PMAPPORT;
 	info->version = PMAPVERS;
@@ -462,6 +474,8 @@ unsigned short rpc_portmap_getport(struct conn_info *info, struct pmap *parms)
 		client = info->client;
 	else {
 		pmap_info.host = info->host;
+		pmap_info.addr = info->addr;
+		pmap_info.addr_len = info->addr_len;
 		pmap_info.port = PMAPPORT;
 		pmap_info.program = PMAPPROG;
 		pmap_info.version = PMAPVERS;
@@ -589,6 +603,8 @@ static unsigned int __rpc_ping(const char *host,
 	struct pmap parms;
 
 	info.host = host;
+	info.addr = NULL;
+	info.addr_len = 0;
 	info.program = NFS_PROGRAM;
 	info.version = version;
 	info.send_sz = 0;
@@ -769,6 +785,8 @@ exports rpc_get_exports(const char *host, long seconds, long micros, unsigned in
 	int status;
 
 	info.host = host;
+	info.addr = NULL;
+	info.addr_len = 0;
 	info.program = MOUNTPROG;
 	info.version = MOUNTVERS;
 	info.send_sz = 0;
diff --git a/modules/replicated.c b/modules/replicated.c
index 90b2925..efbe6b4 100644
--- a/modules/replicated.c
+++ b/modules/replicated.c
@@ -225,7 +225,9 @@ static unsigned int get_proximity(const char *host_addr, int addr_len)
 	return PROXIMITY_OTHER;
 }
 
-static struct host *new_host(const char *name, const char *addr, unsigned int proximity, unsigned int weight)
+static struct host *new_host(const char *name,
+			     const char *addr, size_t addr_len,
+			     unsigned int proximity, unsigned int weight)
 {
 	struct host *new;
 	char *tmp1, *tmp2;
@@ -237,11 +239,12 @@ static struct host *new_host(const char *name, const char *addr, unsigned int pr
 	if (!tmp1)
 		return NULL;
 
-	tmp2 = strdup(addr);
+	tmp2 = malloc(addr_len);
 	if (!tmp2) {
 		free(tmp1);
 		return NULL;
 	}
+	memcpy(tmp2, addr, addr_len);
 
 	new = malloc(sizeof(struct host));
 	if (!new) {
@@ -253,6 +256,7 @@ static struct host *new_host(const char *name, const char *addr, unsigned int pr
 	memset(new, 0, sizeof(struct host));
 
 	new->name = tmp1;
+	new->addr_len = addr_len;
 	new->addr = tmp2;
 	new->proximity = proximity;
 	new->weight = weight;
@@ -437,7 +441,8 @@ static unsigned int get_nfs_info(unsigned logopt, struct host *host,
 v3_ver:
 	if (!have_port_opt) {
 		status = rpc_portmap_getclient(pm_info,
-				 host->name, proto, RPC_CLOSE_DEFAULT);
+				host->name, host->addr, host->addr_len,
+				proto, RPC_CLOSE_DEFAULT);
 		if (!status)
 			goto done_ver;
 	}
@@ -551,6 +556,8 @@ static int get_vers_and_cost(unsigned logopt, struct host *host,
 		timeout = RPC_TIMEOUT * 8;
 
 	rpc_info.host = host->name;
+	rpc_info.addr = host->addr;
+	rpc_info.addr_len = host->addr_len;
 	rpc_info.program = NFS_PROGRAM;
 	rpc_info.timeout.tv_sec = timeout;
 	rpc_info.close_option = RPC_CLOSE_DEFAULT;
@@ -606,6 +613,8 @@ static int get_supported_ver_and_cost(unsigned logopt, struct host *host,
 		timeout = RPC_TIMEOUT * 8;
 
 	rpc_info.host = host->name;
+	rpc_info.addr = host->addr;
+	rpc_info.addr_len = host->addr_len;
 	rpc_info.program = NFS_PROGRAM;
 	rpc_info.timeout.tv_sec = timeout;
 	rpc_info.close_option = RPC_CLOSE_DEFAULT;
@@ -652,7 +661,8 @@ static int get_supported_ver_and_cost(unsigned logopt, struct host *host,
 			return 0;
 	} else {
 		int ret = rpc_portmap_getclient(&pm_info,
-				 host->name, proto, RPC_CLOSE_DEFAULT);
+				host->name, host->addr, host->addr_len,
+				proto, RPC_CLOSE_DEFAULT);
 		if (!ret)
 			return 0;
 
@@ -868,7 +878,7 @@ static int add_host_addrs(struct host **list, const char *host, unsigned int wei
 		if (prx == PROXIMITY_ERROR)
 			return 0;
 
-		if (!(new = new_host(host, thost, prx, weight)))
+		if (!(new = new_host(host, thost, sizeof(saddr.sin_addr), prx, weight)))
 			return 0;
 
 		if (!add_host(list, new))
@@ -891,11 +901,14 @@ static int add_host_addrs(struct host **list, const char *host, unsigned int wei
 	}
 
 	for (haddr = phe->h_addr_list; *haddr; haddr++) {
+		struct in_addr tt;
+
 		prx = get_proximity(*haddr, phe->h_length);
 		if (prx == PROXIMITY_ERROR)
 			return 0;
 
-		if (!(new = new_host(host, *haddr, prx, weight)))
+		memcpy(&tt, *haddr, sizeof(struct in_addr));
+		if (!(new = new_host(host, *haddr, phe->h_length, prx, weight)))
 			return 0;
 
 		if (!add_host(list, new)) {