treewide: rework code to get rid of fixed IPv6 address arrays

[project/odhcpd.git] / src / odhcpd.c

diff --git a/src/odhcpd.c b/src/odhcpd.c
index 8a1c66e..ee628a5 100644 (file)
--- a/src/odhcpd.c
+++ b/src/odhcpd.c
@@ -25,6 +25,7 @@
 #include <signal.h>
 #include <stdbool.h>
 #include <syslog.h>
+#include <alloca.h>
 
 #include <arpa/inet.h>
 #include <net/if.h>
@@ -221,8 +222,7 @@ ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
 
 struct addr_info {
        int ifindex;
-       struct odhcpd_ipaddr *addrs;
-       size_t addrs_sz;
+       struct odhcpd_ipaddr **addrs;
        int pending;
        ssize_t ret;
 };
@@ -230,11 +230,12 @@ struct addr_info {
 static int cb_valid_handler(struct nl_msg *msg, void *arg)
 {
        struct addr_info *ctxt = (struct addr_info *)arg;
+       struct odhcpd_ipaddr *addrs = *(ctxt->addrs);
        struct nlmsghdr *hdr = nlmsg_hdr(msg);
        struct ifaddrmsg *ifa;
        struct nlattr *nla[__IFA_MAX];
 
-       if (hdr->nlmsg_type != RTM_NEWADDR || ctxt->ret >= (ssize_t)ctxt->addrs_sz)
+       if (hdr->nlmsg_type != RTM_NEWADDR)
                return NL_SKIP;
 
        ifa = NLMSG_DATA(hdr);
@@ -246,23 +247,28 @@ static int cb_valid_handler(struct nl_msg *msg, void *arg)
        if (!nla[IFA_ADDRESS])
                return NL_SKIP;
 
-       memset(&ctxt->addrs[ctxt->ret], 0, sizeof(ctxt->addrs[ctxt->ret]));
-       ctxt->addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
+       addrs = realloc(addrs, sizeof(*addrs)*(ctxt->ret + 1));
+       if (!addrs)
+               return NL_SKIP;
+
+       memset(&addrs[ctxt->ret], 0, sizeof(addrs[ctxt->ret]));
+       addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
 
-       nla_memcpy(&ctxt->addrs[ctxt->ret].addr, nla[IFA_ADDRESS],
-                       sizeof(ctxt->addrs[ctxt->ret].addr));
+       nla_memcpy(&addrs[ctxt->ret].addr, nla[IFA_ADDRESS],
+                       sizeof(addrs[ctxt->ret].addr));
 
        if (nla[IFA_CACHEINFO]) {
                struct ifa_cacheinfo *ifc = nla_data(nla[IFA_CACHEINFO]);
 
-               ctxt->addrs[ctxt->ret].preferred = ifc->ifa_prefered;
-               ctxt->addrs[ctxt->ret].valid = ifc->ifa_valid;
+               addrs[ctxt->ret].preferred = ifc->ifa_prefered;
+               addrs[ctxt->ret].valid = ifc->ifa_valid;
        }
 
        if (ifa->ifa_flags & IFA_F_DEPRECATED)
-               ctxt->addrs[ctxt->ret].preferred = 0;
+               addrs[ctxt->ret].preferred = 0;
 
        ctxt->ret++;
+       *(ctxt->addrs) = addrs;
 
        return NL_OK;
 }
@@ -288,8 +294,7 @@ static int cb_error_handler(_unused struct sockaddr_nl *nla, struct nlmsgerr *er
 }
 
 // Detect an IPV6-address currently assigned to the given interface
-ssize_t odhcpd_get_interface_addresses(int ifindex,
-               struct odhcpd_ipaddr *addrs, size_t cnt)
+ssize_t odhcpd_get_interface_addresses(int ifindex, struct odhcpd_ipaddr **addrs)
 {
        struct nl_msg *msg;
        struct ifaddrmsg ifa = {
@@ -302,7 +307,6 @@ ssize_t odhcpd_get_interface_addresses(int ifindex,
        struct addr_info ctxt = {
                .ifindex = ifindex,
                .addrs = addrs,
-               .addrs_sz = cnt,
                .ret = 0,
                .pending = 1,
        };