confd: Create an enumerator for interface types

This has multiple advantages:

- Less chances of typos is repeated "infix-if-type:foo" strings
  scattered throughout the code

- We can lean on GCC's `-Werror=switch` to make sure that iface
  specific logic always handles all types (which was not always the
  case - see follow-up commits)

- We can potentially create a `struct afspec_ops` in the future, which
  could then be indexed by this enum

src/confd/src/cni.c

@@ -6,6 +6,7 @@
 
 #include "core.h"
 #include "cni.h"
+#include "ietf-interfaces.h"
 
 #define CNI_NAME "/etc/cni/net.d/%s.conflist"
 
@@ -86,13 +87,13 @@ FILE *cni_popen(const char *fmt, const char *ifname)
 	return popenf("re", "nsenter -t %d -n %s", pid, cmd);
 }
 
-static bool iface_is_cni(const char *ifname, struct lyd_node *node, const char **type)
+static bool iface_is_cni(const char *ifname, struct lyd_node *node, enum iftype *type)
 {
 	struct lyd_node *net = lydx_get_child(node, "container-network");
 
 	if (net) {
 		if (type)
-			*type = lydx_get_cattr(net, "type");
+			*type = iftype_from_iface(net);
 		return true;
 	}
 
@@ -365,9 +366,7 @@ static int iface_gen_cni(const char *ifname, struct lyd_node *cif)
 	 * "container-network": {}, so someone does their job.
 	 */
 	if (!type) {
-		const char *iftype = lydx_get_cattr(cif, "type");
-
-		if (iftype && !strcmp(iftype, "infix-if-type:bridge"))
+		if (iftype_from_iface(cif) == IFT_BRIDGE)
 			type = "infix-interfaces:bridge";
 		else
 			type = "infix-interfaces:host";
@@ -386,7 +385,7 @@ static int iface_gen_cni(const char *ifname, struct lyd_node *cif)
 int cni_netdag_gen_iface(struct dagger *net, const char *ifname,
 			 struct lyd_node *dif, struct lyd_node *cif)
 {
-	const char *cni_type = NULL;
+	enum iftype cni_type;
 	FILE *fp;
 
 	if (iface_is_cni(ifname, cif, &cni_type)) {
@@ -403,7 +402,7 @@ int cni_netdag_gen_iface(struct dagger *net, const char *ifname,
 		err = iface_gen_cni(ifname, cif);
 		if (err)
 			return err;
-		if (cni_type && !strcmp(cni_type, "bridge"))
+		if (cni_type == IFT_BRIDGE)
 			return 1; /* CNI bridges are managed by podman */
 	} else if (iface_is_cni(ifname, dif, &cni_type)) {
 		/* No longer a container-network, clean up. */
@@ -414,7 +413,7 @@ int cni_netdag_gen_iface(struct dagger *net, const char *ifname,
 		fprintf(fp, "container -a -f delete network %s >/dev/null\n", ifname);
 		fclose(fp);
 
-		if (cni_type && !strcmp(cni_type, "bridge"))
+		if (cni_type == IFT_BRIDGE)
 			return 1; /* CNI bridges are managed by podman */
 	}
 

src/confd/src/ieee802-ethernet-interface.c

@@ -104,7 +104,6 @@ out:
 int netdag_gen_ethtool(struct dagger *net, struct lyd_node *cif, struct lyd_node *dif)
 {
 	struct lyd_node *eth = lydx_get_child(dif, "ethernet");
-	const char *type = lydx_get_cattr(cif, "type");
 	int err;
 
 	/*
@@ -121,7 +120,7 @@ int netdag_gen_ethtool(struct dagger *net, struct lyd_node *cif, struct lyd_node
 	 *
 	 *             Hence this "redundant" check.
 	 */
-	if (strcmp(type, "infix-if-type:ethernet"))
+	if (iftype_from_iface(cif) != IFT_ETH)
 		return 0;
 
 	if (!eth)

src/confd/src/ietf-interfaces.c

@@ -383,58 +383,62 @@ static int netdag_gen_afspec_add(sr_session_ctx_t *session, struct dagger *net,
 				 struct lyd_node *cif, FILE *ip)
 {
 	const char *ifname = lydx_get_cattr(cif, "name");
-	const char *iftype = lydx_get_cattr(cif, "type");
-	int err = 0;
 
 	DEBUG_IFACE(dif, "");
 
-	if (!strcmp(iftype, "infix-if-type:bridge")) {
-		err = bridge_gen(dif, cif, ip, 1);
-	} else if (!strcmp(iftype, "infix-if-type:dummy")) {
-		err = netdag_gen_dummy(net, NULL, cif, ip);
-	} else if (!strcmp(iftype, "infix-if-type:veth")) {
-		err = netdag_gen_veth(net, NULL, cif, ip);
-	} else if (!strcmp(iftype, "infix-if-type:vlan")) {
-		err = netdag_gen_vlan(net, NULL, cif, ip);
-	} else if (!strcmp(iftype, "infix-if-type:ethernet")) {
-		sr_session_set_error_message(net->session, "Cannot create fixed Ethernet interface %s,"
-					     " wrong type or name.", ifname);
-		return -ENOENT;
-	} else if (!strcmp(iftype, "infix-if-type:gre") || !strcmp(iftype, "infix-if-type:gretap")) {
-		err = gre_gen(net, NULL, cif, ip);
-	} else if (!strcmp(iftype, "infix-if-type:vxlan")) {
-		err = vxlan_gen(net, NULL, cif, ip);
-	} else {
-		sr_session_set_error_message(net->session, "%s: unsupported interface type \"%s\"", ifname, iftype);
+	switch (iftype_from_iface(cif)) {
+	case IFT_BRIDGE:
+		return bridge_gen(dif, cif, ip, 1);
+	case IFT_DUMMY:
+		return netdag_gen_dummy(net, NULL, cif, ip);
+	case IFT_GRE:
+	case IFT_GRETAP:
+		return gre_gen(net, NULL, cif, ip);
+	case IFT_VETH:
+		return netdag_gen_veth(net, NULL, cif, ip);
+	case IFT_VLAN:
+		return netdag_gen_vlan(net, NULL, cif, ip);
+	case IFT_VXLAN:
+		return vxlan_gen(net, NULL, cif, ip);
+
+	case IFT_ETH:
+	case IFT_ETHISH:
+	case IFT_UNKNOWN:
+		sr_session_set_error_message(net->session, "%s: unsupported interface type \"%s\"",
+					     ifname, lydx_get_cattr(cif, "type"));
 		return -ENOSYS;
 	}
 
-	if (err)
-		return err;
-
-	return 0;
+	__builtin_unreachable();
+	return -EINVAL;
 }
 
 static int netdag_gen_afspec_set(sr_session_ctx_t *session, struct dagger *net, struct lyd_node *dif,
 				 struct lyd_node *cif, FILE *ip)
 {
-	const char *ifname = lydx_get_cattr(cif, "name");
-	const char *iftype = lydx_get_cattr(cif, "type");
-
 	DEBUG_IFACE(dif, "");
 
-	if (!strcmp(iftype, "infix-if-type:bridge"))
+	switch (iftype_from_iface(cif)) {
+	case IFT_BRIDGE:
 		return bridge_gen(dif, cif, ip, 0);
-	if (!strcmp(iftype, "infix-if-type:vlan"))
+	case IFT_VLAN:
 		return netdag_gen_vlan(net, dif, cif, ip);
-	if (!strcmp(iftype, "infix-if-type:veth"))
+	case IFT_GRETAP:
+	case IFT_VETH:
+	case IFT_VXLAN:
 		return 0;
-	if (!strcmp(iftype, "infix-if-type:gretap"))
-		return 0;
-	if (!strcmp(iftype, "infix-if-type:vxlan"))
-		return 0;
-	ERROR("%s: unsupported interface type \"%s\"", ifname, iftype);
-	return -ENOSYS;
+
+	case IFT_DUMMY:
+	case IFT_ETH:
+	case IFT_ETHISH:
+	case IFT_GRE:
+	case IFT_UNKNOWN:
+		return ERR_IFACE(cif, -ENOSYS, "unsupported interface type \"%s\"",
+				 lydx_get_cattr(cif, "type"));
+	}
+
+	__builtin_unreachable();
+	return -EINVAL;
 }
 
 static bool is_phys_addr_deleted(struct lyd_node *dif)
@@ -449,33 +453,28 @@ static bool is_phys_addr_deleted(struct lyd_node *dif)
 
 static bool netdag_must_del(struct lyd_node *dif, struct lyd_node *cif)
 {
-	const char *iftype = lydx_get_cattr(cif, "type");
-
-	if (strcmp(iftype, "infix-if-type:ethernet") &&
-	    strcmp(iftype, "infix-if-type:etherlike")) {
-		if (is_phys_addr_deleted(dif))
-			return true;
-	}
-
-	if (!strcmp(iftype, "infix-if-type:vlan")) {
-		if (lydx_get_descendant(lyd_child(dif), "vlan", NULL))
-			return true;
-	} else if (!strcmp(iftype, "infix-if-type:veth")) {
-		if (lydx_get_descendant(lyd_child(dif), "veth", NULL))
-			return true;
-	} else if (!strcmp(iftype, "infix-if-type:gre") || !strcmp(iftype, "infix-if-type:gretap")) {
-		if (lydx_get_descendant(lyd_child(dif), "gre", NULL))
-			return true;
-	} else if (!strcmp(iftype, "infix-if-type:vxlan")) {
-		if (lydx_get_descendant(lyd_child(dif), "vxlan", NULL))
-			return true;
-/*
-	} else if (!strcmp(iftype, "infix-if-type:lag")) {
-		if (is_phys_addr_deleted(dif))
-			return true;
-
-		... REMEMBER WHEN ADDING BOND SUPPORT ...
-*/
+	switch (iftype_from_iface(cif)) {
+	case IFT_BRIDGE:
+	case IFT_DUMMY:
+		break;
+	case IFT_ETH:
+	case IFT_ETHISH:
+	/* case IFT_LAG: */
+	/* 	... REMEMBER WHEN ADDING BOND SUPPORT ... */
+		return is_phys_addr_deleted(dif);
+	case IFT_GRE:
+	case IFT_GRETAP:
+		return lydx_get_descendant(lyd_child(dif), "gre", NULL);
+	case IFT_VLAN:
+		return lydx_get_descendant(lyd_child(dif), "vlan", NULL);
+	case IFT_VETH:
+		return lydx_get_descendant(lyd_child(dif), "veth", NULL);
+	case IFT_VXLAN:
+		return lydx_get_descendant(lyd_child(dif), "vxlan", NULL);
+	case IFT_UNKNOWN:
+		ERR_IFACE(cif, -EINVAL, "unsupported interface type \"%s\"",
+			  lydx_get_cattr(cif, "type"));
+		return true;
 	}
 
 	return false;
@@ -485,7 +484,6 @@ static int netdag_gen_iface_del(struct dagger *net, struct lyd_node *dif,
 				       struct lyd_node *cif, bool fixed)
 {
 	const char *ifname = lydx_get_cattr(dif, "name");
-	const char *iftype = lydx_get_cattr(dif, "type");
 	FILE *ip;
 
 	DEBUG_IFACE(dif, "");
@@ -493,7 +491,7 @@ static int netdag_gen_iface_del(struct dagger *net, struct lyd_node *dif,
 	if (dagger_should_skip_current(net, ifname))
 		return 0;
 
-	if (iftype && !strcmp(iftype, "infix-if-type:veth")) {
+	if (iftype_from_iface(cif) == IFT_VETH) {
 		struct lyd_node *node;
 		const char *peer;
 

src/confd/src/ietf-interfaces.h

@@ -21,6 +21,44 @@
 
 #define ONOFF(boolean) boolean ? "on" : "off"
 
+#define IFTYPES(_map) \
+	_map(IFT_BRIDGE, "infix-if-type:bridge")	\
+	_map(IFT_DUMMY,  "infix-if-type:dummy")		\
+	_map(IFT_ETH,    "infix-if-type:ethernet")	\
+	_map(IFT_ETHISH, "infix-if-type:etherlike")	\
+	_map(IFT_GRE,    "infix-if-type:gre")		\
+	_map(IFT_GRETAP, "infix-if-type:gretap")	\
+	_map(IFT_VETH,   "infix-if-type:veth")		\
+	_map(IFT_VLAN,   "infix-if-type:vlan")		\
+	_map(IFT_VXLAN,  "infix-if-type:vxlan")		\
+	/*  */
+
+enum iftype {
+#define ift_enum(_enum, _str) _enum,
+	IFTYPES(ift_enum)
+#undef ift_enum
+
+	IFT_UNKNOWN
+};
+
+static inline enum iftype iftype_from_str(const char *typestr)
+{
+#define ift_cmp(_enum, _str) if (!strcmp(typestr, _str)) return _enum;
+	IFTYPES(ift_cmp)
+#undef ift_cmp
+	return IFT_UNKNOWN;
+}
+
+static inline enum iftype iftype_from_iface(struct lyd_node *ifn)
+{
+	const char *typestr = lydx_get_cattr(ifn, "type");
+
+	if (!typestr)
+		return IFT_UNKNOWN;
+
+	return iftype_from_str(typestr);
+}
+
 static inline const char *bridge_tagtype2str(const char *type)
 {
 	if (!strcmp(type, "ieee802-dot1q-types:c-vlan"))

src/confd/src/infix-if-bridge-mcd.c

@@ -97,7 +97,7 @@ int bridge_mcd_gen(struct lyd_node *cifs)
 		return -EIO;
 
 	LYX_LIST_FOR_EACH(cifs, cif, "interface") {
-		if (strcmp(lydx_get_cattr(cif, "type"), "infix-if-type:bridge"))
+		if (iftype_from_iface(cif) != IFT_BRIDGE)
 			continue;
 
 		err = gen_bridge(cif, conf);

src/confd/src/infix-if-gre.c

@@ -6,13 +6,12 @@
 int gre_gen(struct dagger *net, struct lyd_node *dif,
 	    struct lyd_node *cif, FILE *ip)
 {
-	const char *ifname, *iftype, *local, *remote, *mac = NULL;
+	const char *ifname, *local, *remote, *mac = NULL;
 	struct lyd_node *node = NULL;
 	char gretype[10] = "";
 	int  ipv6;
 
 	ifname = lydx_get_cattr(cif, "name");
-	iftype = lydx_get_cattr(cif, "type");
 
 	node = lydx_get_descendant(lyd_child(cif), "gre", NULL);
 	if (!node)
@@ -22,13 +21,16 @@ int gre_gen(struct dagger *net, struct lyd_node *dif,
 	remote = lydx_get_cattr(node, "remote");
 	ipv6 = !!strstr(local, ":");
 
-	if (!strcmp(iftype, "infix-if-type:gre")) {
+	switch (iftype_from_iface(cif)) {
+	case IFT_GRE:
 		snprintf(gretype, sizeof(gretype), "%sgre", ipv6 ? "ip6" : "");
-
-	}
-	else if (!strcmp(iftype, "infix-if-type:gretap")) {
+		break;
+	case IFT_GRETAP:
 		snprintf(gretype, sizeof(gretype), "%sgretap", ipv6 ? "ip6" : "");
 		mac = get_phys_addr(cif, NULL);
+		break;
+	default:
+		return -EINVAL;
 	}
 
 	fprintf(ip, "link add name %s type %s local %s remote %s", ifname, gretype, local, remote);