gtp: prepare for IPv6 support

Use union artifact to prepare for IPv6 support.
Add and use GTP_{IPV4,TH}_MAXLEN.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index 0522b20242ba8f960e7dccdb5bf024b98783ab61..811e4a6606365e4134797347b764ec69ffdec1be 100644 (file)
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -50,8 +50,12 @@ struct pdp_ctx {
        u8                      gtp_version;
        u16                     af;
 
-       struct in_addr          ms_addr_ip4;
-       struct in_addr          peer_addr_ip4;
+       union {
+               struct in_addr  addr;
+       } ms;
+       union {
+               struct in_addr  addr;
+       } peer;
 
        struct sock             *sk;
        struct net_device       *dev;
@@ -80,9 +84,15 @@ struct gtp_dev {
 };
 
 struct echo_info {
-       struct in_addr          ms_addr_ip4;
-       struct in_addr          peer_addr_ip4;
+       u16                     af;
        u8                      gtp_version;
+
+       union {
+               struct in_addr  addr;
+       } ms;
+       union {
+               struct in_addr  addr;
+       } peer;
 };
 
 static unsigned int gtp_net_id __read_mostly;
@@ -163,7 +173,7 @@ static struct pdp_ctx *ipv4_pdp_find(struct gtp_dev *gtp, __be32 ms_addr)
 
        hlist_for_each_entry_rcu(pdp, head, hlist_addr) {
                if (pdp->af == AF_INET &&
-                   pdp->ms_addr_ip4.s_addr == ms_addr)
+                   pdp->ms.addr.s_addr == ms_addr)
                        return pdp;
        }
 
@@ -181,9 +191,9 @@ static bool gtp_check_ms_ipv4(struct sk_buff *skb, struct pdp_ctx *pctx,
        iph = (struct iphdr *)(skb->data + hdrlen);
 
        if (role == GTP_ROLE_SGSN)
-               return iph->daddr == pctx->ms_addr_ip4.s_addr;
+               return iph->daddr == pctx->ms.addr.s_addr;
        else
-               return iph->saddr == pctx->ms_addr_ip4.s_addr;
+               return iph->saddr == pctx->ms.addr.s_addr;
 }
 
 /* Check if the inner IP address in this packet is assigned to any
@@ -292,13 +302,39 @@ static void gtp0_build_echo_msg(struct gtp0_header *hdr, __u8 msg_type)
                hdr->length = 0;
 }
 
+static int gtp0_send_echo_resp_ip(struct gtp_dev *gtp, struct sk_buff *skb)
+{
+       struct iphdr *iph = ip_hdr(skb);
+       struct flowi4 fl4;
+       struct rtable *rt;
+
+       /* find route to the sender,
+        * src address becomes dst address and vice versa.
+        */
+       rt = ip4_route_output_gtp(&fl4, gtp->sk0, iph->saddr, iph->daddr);
+       if (IS_ERR(rt)) {
+               netdev_dbg(gtp->dev, "no route for echo response from %pI4\n",
+                          &iph->saddr);
+               return -1;
+       }
+
+       udp_tunnel_xmit_skb(rt, gtp->sk0, skb,
+                           fl4.saddr, fl4.daddr,
+                           iph->tos,
+                           ip4_dst_hoplimit(&rt->dst),
+                           0,
+                           htons(GTP0_PORT), htons(GTP0_PORT),
+                           !net_eq(sock_net(gtp->sk1u),
+                                   dev_net(gtp->dev)),
+                           false);
+
+       return 0;
+}
+
 static int gtp0_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
 {
        struct gtp0_packet *gtp_pkt;
        struct gtp0_header *gtp0;
-       struct rtable *rt;
-       struct flowi4 fl4;
-       struct iphdr *iph;
        __be16 seq;
 
        gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr));
@@ -325,27 +361,15 @@ static int gtp0_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
        gtp_pkt->ie.tag = GTPIE_RECOVERY;
        gtp_pkt->ie.val = gtp->restart_count;
 
-       iph = ip_hdr(skb);
-
-       /* find route to the sender,
-        * src address becomes dst address and vice versa.
-        */
-       rt = ip4_route_output_gtp(&fl4, gtp->sk0, iph->saddr, iph->daddr);
-       if (IS_ERR(rt)) {
-               netdev_dbg(gtp->dev, "no route for echo response from %pI4\n",
-                          &iph->saddr);
+       switch (gtp->sk0->sk_family) {
+       case AF_INET:
+               if (gtp0_send_echo_resp_ip(gtp, skb) < 0)
+                       return -1;
+               break;
+       case AF_INET6:
                return -1;
        }
 
-       udp_tunnel_xmit_skb(rt, gtp->sk0, skb,
-                           fl4.saddr, fl4.daddr,
-                           iph->tos,
-                           ip4_dst_hoplimit(&rt->dst),
-                           0,
-                           htons(GTP0_PORT), htons(GTP0_PORT),
-                           !net_eq(sock_net(gtp->sk1u),
-                                   dev_net(gtp->dev)),
-                           false);
        return 0;
 }
 
@@ -360,8 +384,8 @@ static int gtp_genl_fill_echo(struct sk_buff *skb, u32 snd_portid, u32 snd_seq,
                goto failure;
 
        if (nla_put_u32(skb, GTPA_VERSION, echo.gtp_version) ||
-           nla_put_be32(skb, GTPA_PEER_ADDRESS, echo.peer_addr_ip4.s_addr) ||
-           nla_put_be32(skb, GTPA_MS_ADDRESS, echo.ms_addr_ip4.s_addr))
+           nla_put_be32(skb, GTPA_PEER_ADDRESS, echo.peer.addr.s_addr) ||
+           nla_put_be32(skb, GTPA_MS_ADDRESS, echo.ms.addr.s_addr))
                goto failure;
 
        genlmsg_end(skb, genlh);
@@ -372,12 +396,20 @@ failure:
        return -EMSGSIZE;
 }
 
+static void gtp0_handle_echo_resp_ip(struct sk_buff *skb, struct echo_info *echo)
+{
+       struct iphdr *iph = ip_hdr(skb);
+
+       echo->ms.addr.s_addr = iph->daddr;
+       echo->peer.addr.s_addr = iph->saddr;
+       echo->gtp_version = GTP_V0;
+}
+
 static int gtp0_handle_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
 {
        struct gtp0_header *gtp0;
        struct echo_info echo;
        struct sk_buff *msg;
-       struct iphdr *iph;
        int ret;
 
        gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr));
@@ -385,10 +417,13 @@ static int gtp0_handle_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
        if (!gtp0_validate_echo_hdr(gtp0))
                return -1;
 
-       iph = ip_hdr(skb);
-       echo.ms_addr_ip4.s_addr = iph->daddr;
-       echo.peer_addr_ip4.s_addr = iph->saddr;
-       echo.gtp_version = GTP_V0;
+       switch (gtp->sk0->sk_family) {
+       case AF_INET:
+               gtp0_handle_echo_resp_ip(skb, &echo);
+               break;
+       case AF_INET6:
+               return -1;
+       }
 
        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
        if (!msg)
@@ -549,8 +584,8 @@ static int gtp1u_handle_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
                return -1;
 
        iph = ip_hdr(skb);
-       echo.ms_addr_ip4.s_addr = iph->daddr;
-       echo.peer_addr_ip4.s_addr = iph->saddr;
+       echo.ms.addr.s_addr = iph->daddr;
+       echo.peer.addr.s_addr = iph->saddr;
        echo.gtp_version = GTP_V1;
 
        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
@@ -801,9 +836,15 @@ static inline void gtp1_push_header(struct sk_buff *skb, struct pdp_ctx *pctx)
 
 struct gtp_pktinfo {
        struct sock             *sk;
-       struct iphdr            *iph;
-       struct flowi4           fl4;
-       struct rtable           *rt;
+       union {
+               struct iphdr    *iph;
+       };
+       union {
+               struct flowi4   fl4;
+       };
+       union {
+               struct rtable   *rt;
+       };
        struct pdp_ctx          *pctx;
        struct net_device       *dev;
        __be16                  gtph_port;
@@ -864,18 +905,18 @@ static int gtp_build_skb_ip4(struct sk_buff *skb, struct net_device *dev,
        }
        netdev_dbg(dev, "found PDP context %p\n", pctx);
 
-       rt = ip4_route_output_gtp(&fl4, pctx->sk, pctx->peer_addr_ip4.s_addr,
+       rt = ip4_route_output_gtp(&fl4, pctx->sk, pctx->peer.addr.s_addr,
                                  inet_sk(pctx->sk)->inet_saddr);
        if (IS_ERR(rt)) {
                netdev_dbg(dev, "no route to SSGN %pI4\n",
-                          &pctx->peer_addr_ip4.s_addr);
+                          &pctx->peer.addr.s_addr);
                dev->stats.tx_carrier_errors++;
                goto err;
        }
 
        if (rt->dst.dev == dev) {
                netdev_dbg(dev, "circular route to SSGN %pI4\n",
-                          &pctx->peer_addr_ip4.s_addr);
+                          &pctx->peer.addr.s_addr);
                dev->stats.collisions++;
                goto err_rt;
        }
@@ -977,11 +1018,11 @@ static const struct device_type gtp_type = {
        .name = "gtp",
 };
 
+#define GTP_TH_MAXLEN  (sizeof(struct udphdr) + sizeof(struct gtp0_header))
+#define GTP_IPV4_MAXLEN        (sizeof(struct iphdr) + GTP_TH_MAXLEN)
+
 static void gtp_link_setup(struct net_device *dev)
 {
-       unsigned int max_gtp_header_len = sizeof(struct iphdr) +
-                                         sizeof(struct udphdr) +
-                                         sizeof(struct gtp0_header);
        struct gtp_dev *gtp = netdev_priv(dev);
 
        dev->netdev_ops         = &gtp_netdev_ops;
@@ -990,7 +1031,7 @@ static void gtp_link_setup(struct net_device *dev)
 
        dev->hard_header_len = 0;
        dev->addr_len = 0;
-       dev->mtu = ETH_DATA_LEN - max_gtp_header_len;
+       dev->mtu = ETH_DATA_LEN - GTP_IPV4_MAXLEN;
 
        /* Zero header length. */
        dev->type = ARPHRD_NONE;
@@ -1001,7 +1042,7 @@ static void gtp_link_setup(struct net_device *dev)
        dev->features   |= NETIF_F_LLTX;
        netif_keep_dst(dev);
 
-       dev->needed_headroom    = LL_MAX_HEADER + max_gtp_header_len;
+       dev->needed_headroom    = LL_MAX_HEADER + GTP_IPV4_MAXLEN;
        gtp->dev = dev;
 }
 
@@ -1341,9 +1382,9 @@ static void ipv4_pdp_fill(struct pdp_ctx *pctx, struct genl_info *info)
 {
        pctx->gtp_version = nla_get_u32(info->attrs[GTPA_VERSION]);
        pctx->af = AF_INET;
-       pctx->peer_addr_ip4.s_addr =
+       pctx->peer.addr.s_addr =
                nla_get_be32(info->attrs[GTPA_PEER_ADDRESS]);
-       pctx->ms_addr_ip4.s_addr =
+       pctx->ms.addr.s_addr =
                nla_get_be32(info->attrs[GTPA_MS_ADDRESS]);
 
        switch (pctx->gtp_version) {
@@ -1444,13 +1485,13 @@ static struct pdp_ctx *gtp_pdp_add(struct gtp_dev *gtp, struct sock *sk,
        switch (pctx->gtp_version) {
        case GTP_V0:
                netdev_dbg(dev, "GTPv0-U: new PDP ctx id=%llx ssgn=%pI4 ms=%pI4 (pdp=%p)\n",
-                          pctx->u.v0.tid, &pctx->peer_addr_ip4,
-                          &pctx->ms_addr_ip4, pctx);
+                          pctx->u.v0.tid, &pctx->peer.addr,
+                          &pctx->ms.addr, pctx);
                break;
        case GTP_V1:
                netdev_dbg(dev, "GTPv1-U: new PDP ctx id=%x/%x ssgn=%pI4 ms=%pI4 (pdp=%p)\n",
                           pctx->u.v1.i_tei, pctx->u.v1.o_tei,
-                          &pctx->peer_addr_ip4, &pctx->ms_addr_ip4, pctx);
+                          &pctx->peer.addr, &pctx->ms.addr, pctx);
                break;
        }
 
@@ -1622,8 +1663,8 @@ static int gtp_genl_fill_info(struct sk_buff *skb, u32 snd_portid, u32 snd_seq,
 
        if (nla_put_u32(skb, GTPA_VERSION, pctx->gtp_version) ||
            nla_put_u32(skb, GTPA_LINK, pctx->dev->ifindex) ||
-           nla_put_be32(skb, GTPA_PEER_ADDRESS, pctx->peer_addr_ip4.s_addr) ||
-           nla_put_be32(skb, GTPA_MS_ADDRESS, pctx->ms_addr_ip4.s_addr))
+           nla_put_be32(skb, GTPA_PEER_ADDRESS, pctx->peer.addr.s_addr) ||
+           nla_put_be32(skb, GTPA_MS_ADDRESS, pctx->ms.addr.s_addr))
                goto nla_put_failure;
 
        switch (pctx->gtp_version) {