From e99024620796047034c2d6abbce3535827fb52f6 Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Thu, 12 Apr 2012 20:06:05 -0400
Subject: [PATCH] Move nlbuf onto stack and don't share a single buffer for
 sending and receiving.  Move nlportid into client state structure.

---
 ndhc/config.h  | 1 +
 ndhc/ndhc.c    | 3 ++-
 ndhc/netlink.c | 9 ++++-----
 ndhc/netlink.h | 2 --
 4 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/ndhc/config.h b/ndhc/config.h
index e4b43a2..0a3cc9e 100644
--- a/ndhc/config.h
+++ b/ndhc/config.h
@@ -38,6 +38,7 @@ struct client_state_t {
     int ifsPrevState;
     int listenMode;
     int epollFd, signalFd, listenFd, arpFd, nlFd;
+    int nlPortId;
     uint32_t clientAddr, serverAddr, routerAddr;
     uint32_t lease, renewTime, rebindTime, xid;
     uint8_t routerArp[6], serverArp[6];
diff --git a/ndhc/ndhc.c b/ndhc/ndhc.c
index fcf5744..5fbfd91 100644
--- a/ndhc/ndhc.c
+++ b/ndhc/ndhc.c
@@ -75,6 +75,7 @@ struct client_state_t cs = {
     .listenFd = -1,
     .arpFd = -1,
     .nlFd = -1,
+    .nlPortId = -1,
     .routerArp = "\0\0\0\0\0\0",
     .serverArp = "\0\0\0\0\0\0",
 };
@@ -349,7 +350,7 @@ int main(int argc, char **argv)
         write_pid(pidfile);
     }
 
-    if ((cs.nlFd = nl_open(NETLINK_ROUTE, RTMGRP_LINK, &nlportid)) < 0) {
+    if ((cs.nlFd = nl_open(NETLINK_ROUTE, RTMGRP_LINK, &cs.nlPortId)) < 0) {
         log_line("FATAL - failed to open netlink socket");
         exit(EXIT_FAILURE);
     }
diff --git a/ndhc/netlink.c b/ndhc/netlink.c
index b5520f7..d63ce4c 100644
--- a/ndhc/netlink.c
+++ b/ndhc/netlink.c
@@ -42,9 +42,6 @@
 #include "nl.h"
 #include "state.h"
 
-static char nlbuf[8192];
-int nlportid;
-
 static int nlrtattr_assign(struct nlattr *attr, int type, void *data)
 {
     struct nlattr **tb = data;
@@ -124,22 +121,24 @@ static int nl_process_msgs(const struct nlmsghdr *nlh, void *data)
     return 1;
 }
 
-/* Destroys contents of nlbuf */
 void handle_nl_message(struct client_state_t *cs)
 {
+    char nlbuf[8192];
     ssize_t ret;
     assert(cs->nlFd != -1);
     do {
         ret = nl_recv_buf(cs->nlFd, nlbuf, sizeof nlbuf);
         if (ret == -1)
             break;
-        if (nl_foreach_nlmsg(nlbuf, ret, nlportid, nl_process_msgs, cs) == -1)
+        if (nl_foreach_nlmsg(nlbuf, ret, cs->nlPortId, nl_process_msgs, cs)
+            == -1)
             break;
     } while (ret > 0);
 }
 
 static int nl_sendgetlink(struct client_state_t *cs)
 {
+    char nlbuf[8192];
     struct nlmsghdr *nlh = (struct nlmsghdr *)nlbuf;
 
     memset(nlbuf, 0, sizeof nlbuf);
diff --git a/ndhc/netlink.h b/ndhc/netlink.h
index d19c407..06b04db 100644
--- a/ndhc/netlink.h
+++ b/ndhc/netlink.h
@@ -40,8 +40,6 @@ enum {
     IFS_REMOVED
 };
 
-extern int nlportid;
-
 void handle_nl_message(struct client_state_t *cs);
 int nl_getifdata(struct client_state_t *cs);