netlink: Split nl_addr() into separate operation functions

nl_addr() can perform three quite different operations based on the 'op'
parameter, each of which uses a different subset of the parameters.  Split
them up into a function for each operation.  This does use more lines of
code, but the overlap wasn't that great, and the separated logic is much
easier to follow.

It's also clearer in the callers what we expect the netlink operations to
do, and what information it uses.

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

1 files changed, 139 insertions, 93 deletions

diff --git a/netlink.c b/netlink.c
index a41dc63..a10e84c 100644
--- a/netlink.c
+++ b/netlink.c
@@ -334,17 +334,76 @@ next:
 }
 
 /**
- * nl_addr() - Get/set/copy IP addresses for given interface and address family
- * @op:		Requested operation
+ * nl_addr_get() - Get IP address 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
  * @af:		Address family
- * @addr:	Global address to fill on NL_GET, to set on NL_SET
- * @prefix_len:	Mask or prefix length, set or fetched (for IPv4)
- * @addr_l:	Link-scoped address to fill on NL_GET
+ * @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)
+{
+	struct req_t {
+		struct nlmsghdr nlh;
+		struct ifaddrmsg ifa;
+	} req = {
+		.nlh.nlmsg_type    = RTM_GETADDR,
+		.nlh.nlmsg_flags   = NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP,
+		.nlh.nlmsg_len     = sizeof(req),
+		.nlh.nlmsg_seq     = nl_seq++,
+
+		.ifa.ifa_family    = af,
+		.ifa.ifa_index     = ifi,
+	};
+	struct nlmsghdr *nh;
+	char buf[NLBUFSIZ];
+	ssize_t n;
+
+	if ((n = nl_req(0, buf, &req, req.nlh.nlmsg_len)) < 0)
+		return;
+
+	for (nh = (struct nlmsghdr *)buf;
+	     NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
+	     nh = NLMSG_NEXT(nh, n)) {
+		struct ifaddrmsg *ifa = (struct ifaddrmsg *)NLMSG_DATA(nh);
+		struct rtattr *rta;
+		size_t na;
+
+		if (nh->nlmsg_type != RTM_NEWADDR)
+			continue;
+
+		if (ifa->ifa_index != ifi)
+			continue;
+
+		for (rta = IFA_RTA(ifa), na = RTM_PAYLOAD(nh); RTA_OK(rta, na);
+		     rta = RTA_NEXT(rta, na)) {
+			if (rta->rta_type != IFA_ADDRESS)
+				continue;
+
+			if (af == AF_INET) {
+				memcpy(addr, RTA_DATA(rta), RTA_PAYLOAD(rta));
+				*prefix_len = ifa->ifa_prefixlen;
+			} else if (af == AF_INET6 && addr &&
+				   ifa->ifa_scope == RT_SCOPE_UNIVERSE) {
+				memcpy(addr, RTA_DATA(rta), RTA_PAYLOAD(rta));
+			}
+
+			if (addr_l &&
+			    af == AF_INET6 && ifa->ifa_scope == RT_SCOPE_LINK)
+				memcpy(addr_l, RTA_DATA(rta), RTA_PAYLOAD(rta));
+		}
+	}
+}
+
+/**
+ * nl_add_set() - Set IP addresses for given interface and address family
+ * @ifi:	Interface index
+ * @af:		Address family
+ * @addr:	Global address to set
+ * @prefix_len:	Mask or prefix length to set
  */
-void nl_addr(enum nl_op op, unsigned int ifi, unsigned int ifi_ns,
-	     sa_family_t af, void *addr, int *prefix_len, void *addr_l)
+void nl_addr_set(unsigned int ifi, sa_family_t af, void *addr, int prefix_len)
 {
 	struct req_t {
 		struct nlmsghdr nlh;
@@ -364,125 +423,112 @@ void nl_addr(enum nl_op op, unsigned int ifi, unsigned int ifi_ns,
 			} a6;
 		} set;
 	} req = {
-		.nlh.nlmsg_type    = op == NL_SET ? RTM_NEWADDR : RTM_GETADDR,
-		.nlh.nlmsg_flags   = NLM_F_REQUEST,
+		.nlh.nlmsg_type    = RTM_NEWADDR,
+		.nlh.nlmsg_flags   = NLM_F_REQUEST | NLM_F_ACK |
+				     NLM_F_CREATE | NLM_F_EXCL,
 		.nlh.nlmsg_len     = NLMSG_LENGTH(sizeof(struct ifaddrmsg)),
 		.nlh.nlmsg_seq     = nl_seq++,
 
 		.ifa.ifa_family    = af,
-		.ifa.ifa_index     = op == NL_SET ? ifi_ns : ifi,
-		.ifa.ifa_prefixlen = op == NL_SET ? *prefix_len : 0,
+		.ifa.ifa_index     = ifi,
+		.ifa.ifa_prefixlen = prefix_len,
+		.ifa.ifa_scope	   = RT_SCOPE_UNIVERSE,
 	};
-	ssize_t n, nlmsgs_size;
-	struct ifaddrmsg *ifa;
-	struct nlmsghdr *nh;
-	struct rtattr *rta;
 	char buf[NLBUFSIZ];
-	size_t na;
 
-	if (op == NL_SET) {
-		if (af == AF_INET6) {
-			size_t rta_len = RTA_LENGTH(sizeof(req.set.a6.l));
+	if (af == AF_INET6) {
+		size_t rta_len = RTA_LENGTH(sizeof(req.set.a6.l));
 
-			/* By default, strictly speaking, it's duplicated */
-			req.ifa.ifa_flags = IFA_F_NODAD;
+		/* By default, strictly speaking, it's duplicated */
+		req.ifa.ifa_flags = IFA_F_NODAD;
 
-			req.nlh.nlmsg_len = offsetof(struct req_t, set.a6)
-				+ sizeof(req.set.a6);
+		req.nlh.nlmsg_len = offsetof(struct req_t, set.a6)
+			+ sizeof(req.set.a6);
 
-			memcpy(&req.set.a6.l, addr, sizeof(req.set.a6.l));
-			req.set.a6.rta_l.rta_len = rta_len;
-			req.set.a4.rta_l.rta_type = IFA_LOCAL;
-			memcpy(&req.set.a6.a, addr, sizeof(req.set.a6.a));
-			req.set.a6.rta_a.rta_len = rta_len;
-			req.set.a6.rta_a.rta_type = IFA_ADDRESS;
-		} else {
-			size_t rta_len = RTA_LENGTH(sizeof(req.set.a4.l));
-
-			req.nlh.nlmsg_len = offsetof(struct req_t, set.a4)
-				+ sizeof(req.set.a4);
+		memcpy(&req.set.a6.l, addr, sizeof(req.set.a6.l));
+		req.set.a6.rta_l.rta_len = rta_len;
+		req.set.a4.rta_l.rta_type = IFA_LOCAL;
+		memcpy(&req.set.a6.a, addr, sizeof(req.set.a6.a));
+		req.set.a6.rta_a.rta_len = rta_len;
+		req.set.a6.rta_a.rta_type = IFA_ADDRESS;
+	} else {
+		size_t rta_len = RTA_LENGTH(sizeof(req.set.a4.l));
 
-			req.set.a4.l = req.set.a4.a = *(uint32_t *)addr;
-			req.set.a4.rta_l.rta_len = rta_len;
-			req.set.a4.rta_l.rta_type = IFA_LOCAL;
-			req.set.a4.rta_a.rta_len = rta_len;
-			req.set.a4.rta_a.rta_type = IFA_ADDRESS;
-		}
+		req.nlh.nlmsg_len = offsetof(struct req_t, set.a4)
+			+ sizeof(req.set.a4);
 
-		req.ifa.ifa_scope = RT_SCOPE_UNIVERSE;
-		req.nlh.nlmsg_flags |= NLM_F_CREATE | NLM_F_ACK | NLM_F_EXCL;
-	} else {
-		req.nlh.nlmsg_flags |= NLM_F_DUMP;
+		req.set.a4.l = req.set.a4.a = *(uint32_t *)addr;
+		req.set.a4.rta_l.rta_len = rta_len;
+		req.set.a4.rta_l.rta_type = IFA_LOCAL;
+		req.set.a4.rta_a.rta_len = rta_len;
+		req.set.a4.rta_a.rta_type = IFA_ADDRESS;
 	}
 
-	if ((n = nl_req(op == NL_SET, buf, &req, req.nlh.nlmsg_len)) < 0)
-		return;
+	nl_req(1, buf, &req, req.nlh.nlmsg_len);
+}
 
-	if (op == NL_SET)
+/**
+ * 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
+ * @af:		Address family
+ */
+void nl_addr_dup(unsigned int ifi, unsigned int ifi_ns, sa_family_t af)
+{
+	struct req_t {
+		struct nlmsghdr nlh;
+		struct ifaddrmsg ifa;
+	} req = {
+		.nlh.nlmsg_type    = RTM_GETADDR,
+		.nlh.nlmsg_flags   = NLM_F_REQUEST | NLM_F_DUMP,
+		.nlh.nlmsg_len     = sizeof(req),
+		.nlh.nlmsg_seq     = nl_seq++,
+
+		.ifa.ifa_family    = af,
+		.ifa.ifa_index     = ifi,
+		.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)
 		return;
 
-	nh = (struct nlmsghdr *)buf;
 	nlmsgs_size = n;
 
-	for ( ; NLMSG_OK(nh, n); nh = NLMSG_NEXT(nh, n)) {
+	for (nh = (struct nlmsghdr *)buf;
+	     NLMSG_OK(nh, n) && nh->nlmsg_type != NLMSG_DONE;
+	     nh = NLMSG_NEXT(nh, n)) {
+		struct ifaddrmsg *ifa;
+		struct rtattr *rta;
+		size_t na;
+
 		if (nh->nlmsg_type != RTM_NEWADDR)
-			goto next;
+			continue;
 
-		if (op == NL_DUP) {
-			nh->nlmsg_seq = nl_seq++;
-			nh->nlmsg_pid = 0;
-			nh->nlmsg_flags &= ~NLM_F_DUMP_FILTERED;
-			nh->nlmsg_flags |= NLM_F_REQUEST | NLM_F_ACK |
-					   NLM_F_CREATE;
-		}
+		nh->nlmsg_seq = nl_seq++;
+		nh->nlmsg_pid = 0;
+		nh->nlmsg_flags &= ~NLM_F_DUMP_FILTERED;
+		nh->nlmsg_flags |= NLM_F_REQUEST | NLM_F_ACK | NLM_F_CREATE;
 
 		ifa = (struct ifaddrmsg *)NLMSG_DATA(nh);
 
-		if (op == NL_DUP && (ifa->ifa_scope == RT_SCOPE_LINK ||
-				     ifa->ifa_index != ifi)) {
+		if (ifa->ifa_scope == RT_SCOPE_LINK || ifa->ifa_index != ifi) {
 			ifa->ifa_family = AF_UNSPEC;
-			goto next;
+			continue;
 		}
 
-		if (ifa->ifa_index != ifi)
-			goto next;
-
-		if (op == NL_DUP)
-			ifa->ifa_index = ifi_ns;
+		ifa->ifa_index = ifi_ns;
 
 		for (rta = IFA_RTA(ifa), na = RTM_PAYLOAD(nh); RTA_OK(rta, na);
 		     rta = RTA_NEXT(rta, na)) {
-			if (op == NL_DUP && rta->rta_type == IFA_LABEL)
+			if (rta->rta_type == IFA_LABEL)
 				rta->rta_type = IFA_UNSPEC;
-
-			if (op == NL_DUP || rta->rta_type != IFA_ADDRESS)
-				continue;
-
-			if (af == AF_INET && addr && !*(uint32_t *)addr) {
-				memcpy(addr, RTA_DATA(rta), RTA_PAYLOAD(rta));
-				*prefix_len = ifa->ifa_prefixlen;
-			} else if (af == AF_INET6 && addr &&
-				 ifa->ifa_scope == RT_SCOPE_UNIVERSE &&
-				 IN6_IS_ADDR_UNSPECIFIED(addr)) {
-				memcpy(addr, RTA_DATA(rta), RTA_PAYLOAD(rta));
-			}
-
-			if (addr_l &&
-			    af == AF_INET6 && ifa->ifa_scope == RT_SCOPE_LINK &&
-			    IN6_IS_ADDR_UNSPECIFIED(addr_l))
-				memcpy(addr_l, RTA_DATA(rta), RTA_PAYLOAD(rta));
 		}
-next:
-		if (nh->nlmsg_type == NLMSG_DONE)
-			break;
 	}
 
-	if (op == NL_DUP) {
-		char resp[NLBUFSIZ];
-
-		nh = (struct nlmsghdr *)buf;
-		nl_req(1, resp, nh, nlmsgs_size);
-	}
+	nl_req(1, resp, buf, nlmsgs_size);
 }
 
 /**