From 72c71d35ac7e9ff91ce577257f8d9161ab7d0ee0 Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Mon, 1 Jun 2020 14:50:40 +0200
Subject: [PATCH] gluon-mesh-babel: clean up link-local address handling
- Rename obtain_if_addr() to get_linklocal_address()
- Pass buffer of size INET6_ADDRSTRLEN instead of the oversized NI_MAXHOST
- Check if an address is link-local before converting to a string
- Replace an incorrect use of strncmp() with strcmp()
- Return status to caller
- Streamline control flow
While we're at it, the function handle_neighbour(), which is one of the
callers of get_linklocal_address() is slightly cleaned up as well.
---
package/gluon-mesh-babel/src/respondd.c | 65 +++++++++++++------------
1 file changed, 35 insertions(+), 30 deletions(-)
diff --git a/package/gluon-mesh-babel/src/respondd.c b/package/gluon-mesh-babel/src/respondd.c
index 96195d899..124500a2e 100644
--- a/package/gluon-mesh-babel/src/respondd.c
+++ b/package/gluon-mesh-babel/src/respondd.c
@@ -62,38 +62,40 @@
static struct babelhelper_ctx bhelper_ctx = {};
-static void obtain_if_addr(const char *ifname, char *lladdr) {
+static bool get_linklocal_address(const char *ifname, char lladdr[INET6_ADDRSTRLEN]) {
struct ifaddrs *ifaddr, *ifa;
- int family, n;
+ bool ret = false;
if (getifaddrs(&ifaddr) == -1) {
perror("getifaddrs");
- exit(EXIT_FAILURE);
+ return false;
}
- for (ifa = ifaddr, n = 0; ifa != NULL; ifa = ifa->ifa_next, n++) {
- if (ifa->ifa_addr == NULL)
+ for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
+ if (!ifa->ifa_addr)
continue;
- family = ifa->ifa_addr->sa_family;
+ if (ifa->ifa_addr->sa_family != AF_INET6)
+ continue;
- if ( (family == AF_INET6) && ( ! strncmp(ifname, ifa->ifa_name, strlen(ifname)) ) ) {
- char lhost[INET6_ADDRSTRLEN];
- struct in6_addr *address = &((struct sockaddr_in6*)ifa->ifa_addr)->sin6_addr;
- if (inet_ntop(AF_INET6, address, lhost, INET6_ADDRSTRLEN) == NULL) {
- fprintf(stderr, "obtain_if_addr: could not convert ip to string\n");
- goto cleanup;
- }
+ if (strcmp(ifname, ifa->ifa_name) != 0)
+ continue;
- if (! strncmp("fe80:", lhost, 5) ) {
- snprintf( lladdr, NI_MAXHOST, "%s", lhost );
- goto cleanup;
- }
+ const struct in6_addr *address = &((const struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
+ if (!IN6_IS_ADDR_LINKLOCAL(address))
+ continue;
+
+ if (!inet_ntop(AF_INET6, address, lladdr, INET6_ADDRSTRLEN)) {
+ perror("inet_ntop");
+ continue;
}
+
+ ret = true;
+ break;
}
-cleanup:
freeifaddrs(ifaddr);
+ return ret;
}
@@ -164,9 +166,10 @@ static bool interface_file_exists(const char *ifname, const char *name) {
static void mesh_add_if(const char *ifname, struct json_object *wireless,
struct json_object *tunnel, struct json_object *other) {
- char str_ip[NI_MAXHOST] = {};
+ char str_ip[INET6_ADDRSTRLEN];
- obtain_if_addr(ifname, str_ip);
+ if (!get_linklocal_address(ifname, str_ip))
+ return;
struct json_object *address = json_object_new_string(str_ip);
@@ -193,24 +196,26 @@ static bool handle_neighbour(char **data, void *obj) {
if (data[REACH])
json_object_object_add(neigh, "reachability", json_object_new_double(strtod(data[REACH], NULL)));
- struct json_object *nif = 0;
- if (data[IF] && !json_object_object_get_ex(obj, data[IF], &nif)) {
- char str_ip[NI_MAXHOST] = {};
- obtain_if_addr( (const char*)data[IF], str_ip );
+ if (!data[IF])
+ return true;
+
+ struct json_object *nif;
+ if (!json_object_object_get_ex(obj, data[IF], &nif)) {
+ char str_ip[INET6_ADDRSTRLEN];
nif = json_object_new_object();
- json_object_object_add(nif, "ll-addr", json_object_new_string(str_ip));
+ if (get_linklocal_address(data[IF], str_ip))
+ json_object_object_add(nif, "ll-addr", json_object_new_string(str_ip));
+
json_object_object_add(nif, "protocol", json_object_new_string("babel"));
json_object_object_add(obj, data[IF], nif);
- }
- struct json_object *neighborcollector = 0;
- if (!json_object_object_get_ex(nif, "neighbours", &neighborcollector)) {
- neighborcollector = json_object_new_object();
- json_object_object_add(nif, "neighbours", neighborcollector);
+ json_object_object_add(nif, "neighbours", json_object_new_object());
}
+ struct json_object *neighborcollector;
+ json_object_object_get_ex(nif, "neighbours", &neighborcollector);
json_object_object_add(neighborcollector, data[ADDRESS], neigh);
}
--
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