Follow-up to 8b4688c: fix regression on macOS

libnet has multiple libnet_ifaddrlist(), one for each OS family.  The
changes in PR #150, fixing the aribtrary MAX IP address limit on LInux,
unfortunately broke all other operating systems.

This change is for the "other" operating system that are not Windows.
Tested on macOS.

Issue #150

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

1 files changed, 26 insertions, 4 deletions

diff --git a/src/libnet_if_addr.c b/src/libnet_if_addr.c
index b824a4d..e9b6841 100644
--- a/src/libnet_if_addr.c
+++ b/src/libnet_if_addr.c
@@ -188,10 +188,9 @@ libnet_ifaddrlist(register struct libnet_ifaddr_list **ipaddrp, char *dev, regis
 int
 libnet_ifaddrlist(register struct libnet_ifaddr_list **ipaddrp, char *dev, register char *errbuf)
 {
-    register struct libnet_ifaddr_list *al;
+    static struct libnet_ifaddr_list *ifaddrlist = NULL;
     struct ifreq *ifr, *lifr, *pifr, nifr;
     char device[sizeof(nifr.ifr_name)];
-    static struct libnet_ifaddr_list ifaddrlist[MAX_IPADDR];
     
     char *p;
     struct ifconf ifc;
@@ -232,7 +231,16 @@ libnet_ifaddrlist(register struct libnet_ifaddr_list **ipaddrp, char *dev, regis
     pifr = NULL;
     lifr = (struct ifreq *)&ifc.ifc_buf[ifc.ifc_len];
     
-    al = ifaddrlist;
+    if (!ifaddrlist)
+    {
+        ifaddrlist = calloc(ip_addr_num, sizeof(struct libnet_ifaddr_list));
+        if (!ifaddrlist)
+        {
+            snprintf(errbuf, LIBNET_ERRBUF_SIZE, "%s(): OOM when allocating initial ifaddrlist", __func__);
+            return 0;
+        }
+    }
+
     nipaddr = 0;
 
 #ifdef HAVE_LINUX_PROCFS
@@ -253,6 +261,8 @@ libnet_ifaddrlist(register struct libnet_ifaddr_list **ipaddrp, char *dev, regis
 
     for (ifr = ifc.ifc_req; ifr < lifr; ifr = NEXTIFR(ifr))
     {
+        struct libnet_ifaddr_list *al = &ifaddrlist[nipaddr];
+
 	/* XXX LINUX SOLARIS ifalias */
         p = strchr(ifr->ifr_name, ':');
 	if (p)
@@ -313,8 +323,20 @@ libnet_ifaddrlist(register struct libnet_ifaddr_list **ipaddrp, char *dev, regis
             goto bad;
         }
 
-        ++al;
         ++nipaddr;
+        if (nipaddr == ip_addr_num) {
+            struct libnet_ifaddr_list *tmp;
+
+            /* grow by a factor of 1.5, close enough to golden ratio */
+            ip_addr_num += ip_addr_num >> 2;
+            tmp = realloc(ifaddrlist, ip_addr_num * sizeof(struct libnet_ifaddr_list));
+            if (!tmp) {
+                snprintf(errbuf, LIBNET_ERRBUF_SIZE, "%s(): OOM reallocating ifaddrlist", __func__);
+                break;
+            }
+
+            ifaddrlist = tmp;
+        }
 
 #ifndef HAVE_LINUX_PROCFS
         pifr = ifr;