netlink: Explicitly pass netlink sockets to operations

All the netlink operations currently implicitly use one of the two global
netlink sockets, sometimes depending on an 'ns' parameter.  Change them
all to explicitly take the socket to use (or two sockets to use in the case
of the *_dup() functions).  As well as making these functions strictly more
general, it makes the callers easier to follow because we're passing a
socket variable with a name rather than an unexplained '0' or '1' for the
ns parameter.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[sbrivio: Minor formatting changes in pasta_ns_conf()]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 53 insertions, 39 deletions

diff --git a/netlink.c b/netlink.c
index 47f2ba1..498c687 100644
--- a/netlink.c
+++ b/netlink.c
@@ -38,8 +38,8 @@
 #define NLBUFSIZ	(8192 * sizeof(struct nlmsghdr)) /* See netlink(7) */
 
 /* Socket in init, in target namespace, sequence (just needs to be monotonic) */
-static int nl_sock	= -1;
-static int nl_sock_ns	= -1;
+int nl_sock	= -1;
+int nl_sock_ns	= -1;
 static int nl_seq;
 
 /**
@@ -98,17 +98,17 @@ fail:
 
 /**
  * nl_req() - Send netlink request and read response
- * @ns:		Use netlink socket in namespace
+ * @s:		Netlink socket
  * @buf:	Buffer for response (at least NLBUFSIZ long)
  * @req:	Request with netlink header
  * @len:	Request length
  *
  * Return: received length on success, negative error code on failure
  */
-static int nl_req(int ns, char *buf, const void *req, ssize_t len)
+static int nl_req(int s, char *buf, const void *req, ssize_t len)
 {
-	int s = ns ? nl_sock_ns : nl_sock, done = 0;
 	char flush[NLBUFSIZ];
+	int done = 0;
 	ssize_t n;
 
 	while (!done && (n = recv(s, flush, sizeof(flush), MSG_DONTWAIT)) > 0) {
@@ -133,12 +133,13 @@ static int nl_req(int ns, char *buf, const void *req, ssize_t len)
 
 /**
  * nl_get_ext_if() - Get interface index supporting IP version being probed
+ * @s:	Netlink socket
  * @af:	Address family (AF_INET or AF_INET6) to look for connectivity
  *      for.
  *
  * Return: interface index, 0 if not found
  */
-unsigned int nl_get_ext_if(sa_family_t af)
+unsigned int nl_get_ext_if(int s, sa_family_t af)
 {
 	struct { struct nlmsghdr nlh; struct rtmsg rtm; } req = {
 		.nlh.nlmsg_type	 = RTM_GETROUTE,
@@ -157,7 +158,7 @@ unsigned int nl_get_ext_if(sa_family_t af)
 	ssize_t n;
 	size_t na;
 
-	if ((n = nl_req(0, buf, &req, sizeof(req))) < 0)
+	if ((n = nl_req(s, buf, &req, sizeof(req))) < 0)
 		return 0;
 
 	nh = (struct nlmsghdr *)buf;
@@ -186,11 +187,12 @@ unsigned int nl_get_ext_if(sa_family_t af)
 
 /**
  * nl_route_get_def() - Get default route for given interface and address family
+ * @s:		Netlink socket
  * @ifi:	Interface index
  * @af:		Address family
  * @gw:		Default gateway to fill on NL_GET
  */
-void nl_route_get_def(unsigned int ifi, sa_family_t af, void *gw)
+void nl_route_get_def(int s, unsigned int ifi, sa_family_t af, void *gw)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -216,7 +218,7 @@ void nl_route_get_def(unsigned int ifi, sa_family_t af, void *gw)
 	char buf[NLBUFSIZ];
 	ssize_t n;
 
-	if ((n = nl_req(0, buf, &req, req.nlh.nlmsg_len)) < 0)
+	if ((n = nl_req(s, buf, &req, req.nlh.nlmsg_len)) < 0)
 		return;
 
 	for (nh = (struct nlmsghdr *)buf;
@@ -245,11 +247,12 @@ void nl_route_get_def(unsigned int ifi, sa_family_t af, void *gw)
 
 /**
  * nl_route_set_def() - Set default route for given interface and address family
+ * @s:		Netlink socket
  * @ifi:	Interface index in target namespace
  * @af:		Address family
  * @gw:		Default gateway to set
  */
-void nl_route_set_def(unsigned int ifi, sa_family_t af, void *gw)
+void nl_route_set_def(int s, unsigned int ifi, sa_family_t af, void *gw)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -314,16 +317,19 @@ void nl_route_set_def(unsigned int ifi, sa_family_t af, void *gw)
 		req.set.r4.rta_gw.rta_len = rta_len;
 	}
 
-	nl_req(1, buf, &req, req.nlh.nlmsg_len);
+	nl_req(s, buf, &req, req.nlh.nlmsg_len);
 }
 
 /**
  * nl_route_dup() - Copy routes for given interface and address family
- * @ifi:	Interface index in outer network namespace
- * @ifi_ns:	Interface index in target namespace for NL_SET, NL_DUP
+ * @s_src:	Netlink socket in source namespace
+ * @ifi_src:	Source interface index
+ * @s_dst:	Netlink socket in destination namespace
+ * @ifi_dst:	Interface index in destination namespace
  * @af:		Address family
  */
-void nl_route_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
+void nl_route_dup(int s_src, unsigned int ifi_src,
+		  int s_dst, unsigned int ifi_dst, sa_family_t af)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -343,7 +349,7 @@ void nl_route_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
 
 		.rta.rta_type	  = RTA_OIF,
 		.rta.rta_len	  = RTA_LENGTH(sizeof(unsigned int)),
-		.ifi		  = ifi,
+		.ifi		  = ifi_src,
 	};
 	char buf[NLBUFSIZ], resp[NLBUFSIZ];
 	unsigned dup_routes = 0;
@@ -351,7 +357,7 @@ void nl_route_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
 	struct nlmsghdr *nh;
 	unsigned i;
 
-	if ((n = nl_req(0, buf, &req, req.nlh.nlmsg_len)) < 0)
+	if ((n = nl_req(s_src, buf, &req, req.nlh.nlmsg_len)) < 0)
 		return;
 
 	nlmsgs_size = n;
@@ -376,7 +382,7 @@ void nl_route_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
 		for (rta = RTM_RTA(rtm), na = RTM_PAYLOAD(nh); RTA_OK(rta, na);
 		     rta = RTA_NEXT(rta, na)) {
 			if (rta->rta_type == RTA_OIF)
-				*(unsigned int *)RTA_DATA(rta) = ifi_ns;
+				*(unsigned int *)RTA_DATA(rta) = ifi_dst;
 		}
 	}
 
@@ -389,19 +395,20 @@ void nl_route_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
 	 * avoids the need to calculate dependencies: let the kernel do that.
 	 */
 	for (i = 0; i < dup_routes; i++)
-		nl_req(1, resp, nh, nlmsgs_size);
+		nl_req(s_dst, resp, nh, nlmsgs_size);
 }
 
 /**
  * nl_addr_get() - Get IP address for given interface and address family
+ * @s:		Netlink socket
  * @ifi:	Interface index in outer network namespace
  * @af:		Address family
  * @addr:	Global address to fill
  * @prefix_len:	Mask or prefix length, to fill (for IPv4)
  * @addr_l:	Link-scoped address to fill (for IPv6)
  */
-void nl_addr_get(unsigned int ifi, sa_family_t af, void *addr,
-		 int *prefix_len, void *addr_l)
+void nl_addr_get(int s, unsigned int ifi, sa_family_t af,
+		 void *addr, int *prefix_len, void *addr_l)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -419,7 +426,7 @@ void nl_addr_get(unsigned int ifi, sa_family_t af, void *addr,
 	char buf[NLBUFSIZ];
 	ssize_t n;
 
-	if ((n = nl_req(0, buf, &req, req.nlh.nlmsg_len)) < 0)
+	if ((n = nl_req(s, buf, &req, req.nlh.nlmsg_len)) < 0)
 		return;
 
 	for (nh = (struct nlmsghdr *)buf;
@@ -457,12 +464,14 @@ void nl_addr_get(unsigned int ifi, sa_family_t af, void *addr,
 
 /**
  * nl_add_set() - Set IP addresses for given interface and address family
+ * @s:		Netlink socket
  * @ifi:	Interface index
  * @af:		Address family
  * @addr:	Global address to set
  * @prefix_len:	Mask or prefix length to set
  */
-void nl_addr_set(unsigned int ifi, sa_family_t af, void *addr, int prefix_len)
+void nl_addr_set(int s, unsigned int ifi, sa_family_t af,
+		 void *addr, int prefix_len)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -523,16 +532,19 @@ void nl_addr_set(unsigned int ifi, sa_family_t af, void *addr, int prefix_len)
 		req.set.a4.rta_a.rta_type = IFA_ADDRESS;
 	}
 
-	nl_req(1, buf, &req, req.nlh.nlmsg_len);
+	nl_req(s, buf, &req, req.nlh.nlmsg_len);
 }
 
 /**
  * nl_addr_dup() - Copy IP addresses for given interface and address family
- * @ifi:	Interface index in outer network namespace
- * @ifi_ns:	Interface index in target namespace
+ * @s_src:	Netlink socket in source network namespace
+ * @ifi_src:	Interface index in source network namespace
+ * @s_dst:	Netlink socket in destination network namespace
+ * @ifi_dst:	Interface index in destination namespace
  * @af:		Address family
  */
-void nl_addr_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
+void nl_addr_dup(int s_src, unsigned int ifi_src,
+		 int s_dst, unsigned int ifi_dst, sa_family_t af)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -544,14 +556,14 @@ void nl_addr_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
 		.nlh.nlmsg_seq     = nl_seq++,
 
 		.ifa.ifa_family    = af,
-		.ifa.ifa_index     = ifi,
+		.ifa.ifa_index     = ifi_src,
 		.ifa.ifa_prefixlen = 0,
 	};
 	char buf[NLBUFSIZ], resp[NLBUFSIZ];
 	ssize_t n, nlmsgs_size;
 	struct nlmsghdr *nh;
 
-	if ((n = nl_req(0, buf, &req, sizeof(req))) < 0)
+	if ((n = nl_req(s_src, buf, &req, sizeof(req))) < 0)
 		return;
 
 	nlmsgs_size = n;
@@ -573,12 +585,13 @@ void nl_addr_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
 
 		ifa = (struct ifaddrmsg *)NLMSG_DATA(nh);
 
-		if (ifa->ifa_scope == RT_SCOPE_LINK || ifa->ifa_index != ifi) {
+		if (ifa->ifa_scope == RT_SCOPE_LINK ||
+		    ifa->ifa_index != ifi_src) {
 			ifa->ifa_family = AF_UNSPEC;
 			continue;
 		}
 
-		ifa->ifa_index = ifi_ns;
+		ifa->ifa_index = ifi_dst;
 
 		for (rta = IFA_RTA(ifa), na = RTM_PAYLOAD(nh); RTA_OK(rta, na);
 		     rta = RTA_NEXT(rta, na)) {
@@ -587,16 +600,16 @@ void nl_addr_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
 		}
 	}
 
-	nl_req(1, resp, buf, nlmsgs_size);
+	nl_req(s_dst, resp, buf, nlmsgs_size);
 }
 
 /**
  * nl_link_get_mac() - Get link MAC address
- * @ns:		Use netlink socket in namespace
+ * @s:		Netlink socket
  * @ifi:	Interface index
  * @mac:	Fill with current MAC address
  */
-void nl_link_get_mac(int ns, unsigned int ifi, void *mac)
+void nl_link_get_mac(int s, unsigned int ifi, void *mac)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -613,7 +626,7 @@ void nl_link_get_mac(int ns, unsigned int ifi, void *mac)
 	char buf[NLBUFSIZ];
 	ssize_t n;
 
-	n = nl_req(ns, buf, &req, sizeof(req));
+	n = nl_req(s, buf, &req, sizeof(req));
 	if (n < 0)
 		return;
 
@@ -641,11 +654,12 @@ void nl_link_get_mac(int ns, unsigned int ifi, void *mac)
 
 /**
  * nl_link_set_mac() - Set link MAC address
+ * @s:		Netlink socket
  * @ns:		Use netlink socket in namespace
  * @ifi:	Interface index
  * @mac:	MAC address to set
  */
-void nl_link_set_mac(int ns, unsigned int ifi, void *mac)
+void nl_link_set_mac(int s, unsigned int ifi, void *mac)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -666,16 +680,16 @@ void nl_link_set_mac(int ns, unsigned int ifi, void *mac)
 
 	memcpy(req.mac, mac, ETH_ALEN);
 
-	nl_req(ns, buf, &req, sizeof(req));
+	nl_req(s, buf, &req, sizeof(req));
 }
 
 /**
  * nl_link_up() - Bring link up
- * @ns:		Use netlink socket in namespace
+ * @s:		Netlink socket
  * @ifi:	Interface index
  * @mtu:	If non-zero, set interface MTU
  */
-void nl_link_up(int ns, unsigned int ifi, int mtu)
+void nl_link_up(int s, unsigned int ifi, int mtu)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -701,5 +715,5 @@ void nl_link_up(int ns, unsigned int ifi, int mtu)
 		/* Shorten request to drop MTU attribute */
 		req.nlh.nlmsg_len = offsetof(struct req_t, rta);
 
-	nl_req(ns, buf, &req, req.nlh.nlmsg_len);
+	nl_req(s, buf, &req, req.nlh.nlmsg_len);
 }