Simplify route attribute appending.

Signed-off-by: Benjamin Cama <benoar@dolka.fr>

diff --git a/l2tpns.c b/l2tpns.c
index 9f5e901..57e3215 100644 (file)
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -576,6 +576,19 @@ static ssize_t netlink_recv(void *buf, ssize_t len)
        return recvmsg(nlfd, &msg, 0);
 }
 
+/* adapted from iproute2 */
+void netlink_addattr(struct nlmsghdr *nh, int type, const void *data, int alen)
+{
+       int len = RTA_LENGTH(alen);
+       struct rtattr *rta;
+
+       rta = (struct rtattr *)(((void *)nh) + NLMSG_ALIGN(nh->nlmsg_len));
+       rta->rta_type = type;
+       rta->rta_len = len;
+       memcpy(RTA_DATA(rta), data, alen);
+       nh->nlmsg_len = NLMSG_ALIGN(nh->nlmsg_len) + RTA_ALIGN(len);
+}
+
 // messages corresponding to different phases seq number
 static char *tun_nl_phase_msg[] = {
        "initialized",
@@ -628,15 +641,11 @@ static void inittun(void)
 
                req.nh.nlmsg_type = RTM_GETLINK;
                req.nh.nlmsg_flags = NLM_F_REQUEST;
+               req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifinfo));
 
                req.ifinfo.ifi_family = AF_UNSPEC; // as the man says
 
-               req.ifname_rta.rta_len = RTA_LENGTH(strlen(config->tundevice)+1);
-               req.ifname_rta.rta_type = IFLA_IFNAME;
-               strncpy(req.ifname, config->tundevice, IFNAMSIZ-1);
-
-               req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifinfo)
-                               + req.ifname_rta.rta_len);
+               netlink_addattr(&req.nh, IFLA_IFNAME, config->tundevice, strlen(config->tundevice)+1);
 
                if(netlink_send(&req.nh) < 0 || (len = netlink_recv(buf, sizeof(buf))) < 0)
                {
@@ -665,133 +674,91 @@ static void inittun(void)
                        } ifmsg __attribute__ ((aligned(NLMSG_ALIGNTO)));
                        char rtdata[32]; // 32 should be enough
                } req;
-               struct {
-                       struct rtattr rta;
-                       uint32_t u32 __attribute__ ((aligned(RTA_ALIGNTO)));;
-               } u32_attr;
-               struct {
-                       struct rtattr rta;
-                       struct in_addr addr __attribute__ ((aligned(RTA_ALIGNTO)));;
-               } ipv4_attr;
-               struct {
-                       struct rtattr rta;
-                       struct in6_addr addr6 __attribute__ ((aligned(RTA_ALIGNTO)));;
-               } ipv6_attr;
-               char *buf_ptr;
+               uint32_t txqlen, mtu;
+               struct in_addr ip;
 
                memset(&req, 0, sizeof(req));
 
                req.nh.nlmsg_type = RTM_SETLINK;
                req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_MULTI;
+               req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifmsg.ifinfo));
 
                req.ifmsg.ifinfo = ifinfo;
                req.ifmsg.ifinfo.ifi_flags |= IFF_UP; // set interface up
                req.ifmsg.ifinfo.ifi_change = IFF_UP; // only change this flag
 
-               buf_ptr = NLMSG_DATA(&req.nh) + sizeof(req.ifmsg.ifinfo);
-
-               u32_attr.rta.rta_len = RTA_LENGTH(sizeof(u32_attr.u32));
-               u32_attr.rta.rta_type = IFLA_TXQLEN;
                /* Bump up the qlen to deal with bursts from the network */
-               u32_attr.u32 = 1000;
-               memcpy(buf_ptr, &u32_attr, sizeof(u32_attr));
-
-               buf_ptr += RTA_ALIGN(u32_attr.rta.rta_len);
-
-               u32_attr.rta.rta_len = RTA_LENGTH(sizeof(u32_attr.u32));
-               u32_attr.rta.rta_type = IFLA_MTU;
+               txqlen = 1000;
+               netlink_addattr(&req.nh, IFLA_TXQLEN, &txqlen, sizeof(txqlen));
                /* set MTU to modem MRU */
-               u32_attr.u32 = MRU;
-               memcpy(buf_ptr, &u32_attr, sizeof(u32_attr));
-
-               req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifmsg.ifinfo)
-                               + u32_attr.rta.rta_len * 2);
+               mtu = MRU;
+               netlink_addattr(&req.nh, IFLA_MTU, &mtu, sizeof(mtu));
 
                if (netlink_send(&req.nh) < 0)
-               {
-                       LOG(0, 0, 0, "Error setting up tun device interface: %s\n", strerror(errno));
-                       exit(1);
-               }
+                       goto senderror;
 
                memset(&req, 0, sizeof(req));
 
                req.nh.nlmsg_type = RTM_NEWADDR;
                req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_MULTI;
+               req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifmsg.ifaddr));
 
                req.ifmsg.ifaddr.ifa_family = AF_INET;
                req.ifmsg.ifaddr.ifa_prefixlen = 32;
                req.ifmsg.ifaddr.ifa_index = ifinfo.ifi_index;
 
-               ipv4_attr.rta.rta_len = RTA_LENGTH(sizeof(ipv4_attr.addr));
-               ipv4_attr.rta.rta_type = IFA_LOCAL;
-               ipv4_attr.addr.s_addr = config->bind_address ?
-                       config->bind_address : 0x01010101; // 1.1.1.1
-               memcpy(NLMSG_DATA(&req.nh) + sizeof(req.ifmsg.ifaddr), &ipv4_attr, sizeof(ipv4_attr));
-
-               req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifmsg.ifaddr)
-                               + ipv4_attr.rta.rta_len);
+               if (config->bind_address)
+                       ip.s_addr = config->bind_address;
+               else
+                       ip.s_addr = 0x01010101, // 1.1.1.1
+               netlink_addattr(&req.nh, IFA_LOCAL, &ip, sizeof(ip));
 
                if (netlink_send(&req.nh) < 0)
-               {
-                       LOG(0, 0, 0, "Error setting up tun device IPv4 address: %s\n", strerror(errno));
-                       exit(1);
-               }
+                       goto senderror;
 
                // Only setup IPv6 on the tun device if we have a configured prefix
                if (config->ipv6_prefix.s6_addr[0]) {
+                       struct in6_addr ip6;
+
                        memset(&req, 0, sizeof(req));
 
                        req.nh.nlmsg_type = RTM_NEWADDR;
                        req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_MULTI;
+                       req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifmsg.ifaddr));
 
                        req.ifmsg.ifaddr.ifa_family = AF_INET6;
                        req.ifmsg.ifaddr.ifa_prefixlen = 64;
                        req.ifmsg.ifaddr.ifa_scope = RT_SCOPE_LINK;
                        req.ifmsg.ifaddr.ifa_index = ifinfo.ifi_index;
 
-                       ipv6_attr.rta.rta_len = RTA_LENGTH(sizeof(ipv6_attr.addr6));
-                       ipv6_attr.rta.rta_type = IFA_LOCAL;
                        // Link local address is FE80::1
-                       memset(&ipv6_attr.addr6, 0, sizeof(ipv6_attr.addr6));
-                       ipv6_attr.addr6.s6_addr[0] = 0xFE;
-                       ipv6_attr.addr6.s6_addr[1] = 0x80;
-                       ipv6_attr.addr6.s6_addr[15] = 1;
-                       memcpy(NLMSG_DATA(&req.nh) + sizeof(req.ifmsg.ifaddr), &ipv6_attr, sizeof(ipv6_attr));
-
-                       req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifmsg.ifaddr)
-                                       + ipv6_attr.rta.rta_len);
+                       memset(&ip6, 0, sizeof(ip6));
+                       ip6.s6_addr[0] = 0xFE;
+                       ip6.s6_addr[1] = 0x80;
+                       ip6.s6_addr[15] = 1;
+                       netlink_addattr(&req.nh, IFA_LOCAL, &ip6, sizeof(ip6));
 
                        if (netlink_send(&req.nh) < 0)
-                       {
-                               LOG(0, 0, 0, "Error setting up tun device IPv6 LL address: %s\n", strerror(errno));
-                               exit(1);
-                       }
+                               goto senderror;
 
                        memset(&req, 0, sizeof(req));
 
                        req.nh.nlmsg_type = RTM_NEWADDR;
                        req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_MULTI;
+                       req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifmsg.ifaddr));
 
                        req.ifmsg.ifaddr.ifa_family = AF_INET6;
                        req.ifmsg.ifaddr.ifa_prefixlen = 64;
                        req.ifmsg.ifaddr.ifa_scope = RT_SCOPE_UNIVERSE;
                        req.ifmsg.ifaddr.ifa_index = ifinfo.ifi_index;
 
-                       ipv6_attr.rta.rta_len = RTA_LENGTH(sizeof(ipv6_attr.addr6));
-                       ipv6_attr.rta.rta_type = IFA_LOCAL;
                        // Global address is prefix::1
-                       ipv6_attr.addr6 = config->ipv6_prefix;
-                       ipv6_attr.addr6.s6_addr[15] = 1;
-                       memcpy(NLMSG_DATA(&req.nh) + sizeof(req.ifmsg.ifaddr), &ipv6_attr, sizeof(ipv6_attr));
-
-                       req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.ifmsg.ifaddr)
-                                       + ipv6_attr.rta.rta_len);
+                       ip6 = config->ipv6_prefix;
+                       ip6.s6_addr[15] = 1;
+                       netlink_addattr(&req.nh, IFA_LOCAL, &ip6, sizeof(ip6));
 
                        if (netlink_send(&req.nh) < 0)
-                       {
-                               LOG(0, 0, 0, "Error setting up tun device IPv6 global address: %s\n", strerror(errno));
-                               exit(1);
-                       }
+                               goto senderror;
                }
 
                memset(&req, 0, sizeof(req));
@@ -800,10 +767,7 @@ static void inittun(void)
                req.nh.nlmsg_len = NLMSG_LENGTH(0);
 
                if (netlink_send(&req.nh) < 0)
-               {
-                       LOG(0, 0, 0, "Error finishing setting up tun device: %s\n", strerror(errno));
-                       exit(1);
-               }
+                       goto senderror;
 
                // if we get an error for seqnum < min_initok_nlseqnum,
                // we must exit as initialization went wrong
@@ -812,6 +776,12 @@ static void inittun(void)
                else
                        min_initok_nlseqnum = 3 + 1; // idx + if + addr
        }
+
+       return;
+
+senderror:
+       LOG(0, 0, 0, "Error while setting up tun device: %s\n", strerror(errno));
+       exit(1);
 }
 
 // set up UDP ports