We need a seperate iovec buffer for receiving netlink messages because

we need to send and receive before the first receive has finished.

diff --git a/if-linux.c b/if-linux.c
index 11a8c5fb06496c63c67d8b123de522689bc56066..3b49fd6ac1ce0a63cbcad309f04a135c5584c568 100644 (file)
--- a/if-linux.c
+++ b/if-linux.c
@@ -94,6 +94,7 @@ int if_getssid_wext(const char *ifname, uint8_t *ssid);
 struct priv {
        int route_fd;
        uint32_t route_pid;
+       struct iovec link_iov;
 };
 
 /* Broadcast address for IPoIB */
@@ -299,6 +300,8 @@ if_opensockets_os(struct dhcpcd_ctx *ctx)
        if (getsockname(priv->route_fd, (struct sockaddr *)&snl, &len) == -1)
                return -1;
        priv->route_pid = snl.nl_pid;
+       priv->link_iov.iov_base = NULL;
+       priv->link_iov.iov_len = 0;
        return 0;
 }
 
@@ -309,12 +312,14 @@ if_closesockets_os(struct dhcpcd_ctx *ctx)
 
        if (ctx->priv != NULL) {
                priv = (struct priv *)ctx->priv;
+               free(priv->link_iov.iov_base);
                close(priv->route_fd);
        }
 }
 
 static int
-get_netlink(struct dhcpcd_ctx *ctx, struct interface *ifp, int fd, int flags,
+get_netlink(struct dhcpcd_ctx *ctx, struct iovec *iov,
+    struct interface *ifp, int fd, int flags,
     int (*callback)(struct dhcpcd_ctx *, struct interface *, struct nlmsghdr *))
 {
        struct msghdr msg;
@@ -327,7 +332,7 @@ get_netlink(struct dhcpcd_ctx *ctx, struct interface *ifp, int fd, int flags,
        msg.msg_name = &nladdr;
        msg.msg_namelen = sizeof(nladdr);
        memset(&nladdr, 0, sizeof(nladdr));
-       msg.msg_iov = &ctx->iov;
+       msg.msg_iov = iov;
        msg.msg_iovlen = 1;
        if ((bytes = recvmsg_realloc(fd, &msg, flags)) == -1)
                return -1;
@@ -342,7 +347,7 @@ get_netlink(struct dhcpcd_ctx *ctx, struct interface *ifp, int fd, int flags,
                return 0;
 
        r = 0;
-       for (nlm = ctx->iov.iov_base;
+       for (nlm = iov->iov_base;
             nlm && NLMSG_OK(nlm, (size_t)bytes);
             nlm = NLMSG_NEXT(nlm, bytes))
        {
@@ -851,8 +856,10 @@ link_netlink(struct dhcpcd_ctx *ctx, struct interface *ifp,
 int
 if_handlelink(struct dhcpcd_ctx *ctx)
 {
+       struct priv *priv;
 
-       return get_netlink(ctx, NULL,
+       priv = (struct priv *)ctx->priv;
+       return get_netlink(ctx, &priv->link_iov, NULL,
            ctx->link_fd, MSG_DONTWAIT, &link_netlink);
 }
 
@@ -892,7 +899,7 @@ send_netlink(struct dhcpcd_ctx *ctx, struct interface *ifp,
        hdr->nlmsg_seq = (uint32_t)++ctx->seq;
        if (sendmsg(s, &msg, 0) != -1) {
                ctx->sseq = ctx->seq;
-               r = get_netlink(ctx, ifp, s, 0, callback);
+               r = get_netlink(ctx, &ctx->iov, ifp, s, 0, callback);
        } else
                r = -1;
        if (protocol != NETLINK_ROUTE)