gre6: Cleanup GREv6 transmit path, call common GRE functions
authorTom Herbert <tom@herbertland.com>
Sat, 30 Apr 2016 00:12:21 +0000 (17:12 -0700)
committerDavid S. Miller <davem@davemloft.net>
Mon, 2 May 2016 23:23:32 +0000 (19:23 -0400)
Changes in GREv6 transmit path:
  - Call gre_checksum, remove gre6_checksum
  - Rename ip6gre_xmit2 to __gre6_xmit
  - Call gre_build_header utility function
  - Call ip6_tnl_xmit common function
  - Call ip6_tnl_change_mtu, eliminate ip6gre_tunnel_change_mtu

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv6/ip6_gre.c

index 9b33745761ca770c9e8869e7364d635d5e06bb4d..10127741a60db425daaf42ce60b2101a0f67eabb 100644 (file)
@@ -488,199 +488,40 @@ struct ipv6_tel_txoption {
        __u8 dst_opt[8];
 };
 
-static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
+static int gre_handle_offloads(struct sk_buff *skb, bool csum)
 {
-       memset(opt, 0, sizeof(struct ipv6_tel_txoption));
-
-       opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
-       opt->dst_opt[3] = 1;
-       opt->dst_opt[4] = encap_limit;
-       opt->dst_opt[5] = IPV6_TLV_PADN;
-       opt->dst_opt[6] = 1;
-
-       opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
-       opt->ops.opt_nflen = 8;
+       return iptunnel_handle_offloads(skb,
+                                       csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
 }
 
-static __sum16 gre6_checksum(struct sk_buff *skb)
-{
-       __wsum csum;
-
-       if (skb->ip_summed == CHECKSUM_PARTIAL)
-               csum = lco_csum(skb);
-       else
-               csum = skb_checksum(skb, sizeof(struct ipv6hdr),
-                                   skb->len - sizeof(struct ipv6hdr), 0);
-       return csum_fold(csum);
-}
-
-static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
-                        struct net_device *dev,
-                        __u8 dsfield,
-                        struct flowi6 *fl6,
-                        int encap_limit,
-                        __u32 *pmtu)
+static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
+                              struct net_device *dev, __u8 dsfield,
+                              struct flowi6 *fl6, int encap_limit,
+                              __u32 *pmtu, __be16 proto)
 {
        struct ip6_tnl *tunnel = netdev_priv(dev);
-       struct net *net = tunnel->net;
-       struct net_device *tdev;    /* Device to other host */
-       struct ipv6hdr  *ipv6h;     /* Our new IP header */
-       unsigned int min_headroom = 0; /* The extra header space needed */
-       int    gre_hlen;
-       struct ipv6_tel_txoption opt;
-       int    mtu;
-       struct dst_entry *dst = NULL, *ndst = NULL;
-       struct net_device_stats *stats = &tunnel->dev->stats;
-       int err = -1;
-       u8 proto;
-       __be16 protocol;
+       __be16 protocol = (dev->type == ARPHRD_ETHER) ?
+                         htons(ETH_P_TEB) : proto;
 
        if (dev->type == ARPHRD_ETHER)
                IPCB(skb)->flags = 0;
 
-       if (dev->header_ops && dev->type == ARPHRD_IP6GRE) {
-               gre_hlen = 0;
-               ipv6h = (struct ipv6hdr *)skb->data;
-               fl6->daddr = ipv6h->daddr;
-       } else {
-               gre_hlen = tunnel->hlen;
+       if (dev->header_ops && dev->type == ARPHRD_IP6GRE)
+               fl6->daddr = ((struct ipv6hdr *)skb->data)->daddr;
+       else
                fl6->daddr = tunnel->parms.raddr;
-       }
-
-       if (!fl6->flowi6_mark)
-               dst = dst_cache_get(&tunnel->dst_cache);
-
-       if (!dst) {
-               dst = ip6_route_output(net, NULL, fl6);
-
-               if (dst->error)
-                       goto tx_err_link_failure;
-               dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), NULL, 0);
-               if (IS_ERR(dst)) {
-                       err = PTR_ERR(dst);
-                       dst = NULL;
-                       goto tx_err_link_failure;
-               }
-               ndst = dst;
-       }
-
-       tdev = dst->dev;
-
-       if (tdev == dev) {
-               stats->collisions++;
-               net_warn_ratelimited("%s: Local routing loop detected!\n",
-                                    tunnel->parms.name);
-               goto tx_err_dst_release;
-       }
 
-       mtu = dst_mtu(dst) - sizeof(*ipv6h);
-       if (encap_limit >= 0) {
-               min_headroom += 8;
-               mtu -= 8;
-       }
-       if (mtu < IPV6_MIN_MTU)
-               mtu = IPV6_MIN_MTU;
-       if (skb_dst(skb))
-               skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
-       if (skb->len > mtu && !skb_is_gso(skb)) {
-               *pmtu = mtu;
-               err = -EMSGSIZE;
-               goto tx_err_dst_release;
-       }
+       if (tunnel->parms.o_flags & TUNNEL_SEQ)
+               tunnel->o_seqno++;
 
-       if (tunnel->err_count > 0) {
-               if (time_before(jiffies,
-                               tunnel->err_time + IP6TUNNEL_ERR_TIMEO)) {
-                       tunnel->err_count--;
+       /* Push GRE header. */
+       gre_build_header(skb, tunnel->tun_hlen, tunnel->parms.o_flags,
+                        protocol, tunnel->parms.o_key, htonl(tunnel->o_seqno));
 
-                       dst_link_failure(skb);
-               } else
-                       tunnel->err_count = 0;
-       }
+       skb_set_inner_protocol(skb, proto);
 
-       skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
-
-       min_headroom += LL_RESERVED_SPACE(tdev) + gre_hlen + dst->header_len;
-
-       if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
-               int head_delta = SKB_DATA_ALIGN(min_headroom -
-                                               skb_headroom(skb) +
-                                               16);
-
-               err = pskb_expand_head(skb, max_t(int, head_delta, 0),
-                                      0, GFP_ATOMIC);
-               if (min_headroom > dev->needed_headroom)
-                       dev->needed_headroom = min_headroom;
-               if (unlikely(err))
-                       goto tx_err_dst_release;
-       }
-
-       if (!fl6->flowi6_mark && ndst)
-               dst_cache_set_ip6(&tunnel->dst_cache, ndst, &fl6->saddr);
-       skb_dst_set(skb, dst);
-
-       proto = NEXTHDR_GRE;
-       if (encap_limit >= 0) {
-               init_tel_txopt(&opt, encap_limit);
-               ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
-       }
-
-       err = iptunnel_handle_offloads(skb,
-                                      (tunnel->parms.o_flags & GRE_CSUM) ?
-                                      SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
-       if (err)
-               goto tx_err_dst_release;
-
-       skb_push(skb, gre_hlen);
-       skb_reset_network_header(skb);
-       skb_set_transport_header(skb, sizeof(*ipv6h));
-
-       /*
-        *      Push down and install the IP header.
-        */
-       ipv6h = ipv6_hdr(skb);
-       ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),
-                    ip6_make_flowlabel(net, skb, fl6->flowlabel, true, fl6));
-       ipv6h->hop_limit = tunnel->parms.hop_limit;
-       ipv6h->nexthdr = proto;
-       ipv6h->saddr = fl6->saddr;
-       ipv6h->daddr = fl6->daddr;
-
-       ((__be16 *)(ipv6h + 1))[0] = tunnel->parms.o_flags;
-       protocol = (dev->type == ARPHRD_ETHER) ?
-                   htons(ETH_P_TEB) : skb->protocol;
-       ((__be16 *)(ipv6h + 1))[1] = protocol;
-
-       if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
-               __be32 *ptr = (__be32 *)(((u8 *)ipv6h) + tunnel->hlen - 4);
-
-               if (tunnel->parms.o_flags&GRE_SEQ) {
-                       ++tunnel->o_seqno;
-                       *ptr = htonl(tunnel->o_seqno);
-                       ptr--;
-               }
-               if (tunnel->parms.o_flags&GRE_KEY) {
-                       *ptr = tunnel->parms.o_key;
-                       ptr--;
-               }
-               if ((tunnel->parms.o_flags & GRE_CSUM) &&
-                   !(skb_shinfo(skb)->gso_type &
-                     (SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
-                       *ptr = 0;
-                       *(__sum16 *)ptr = gre6_checksum(skb);
-               }
-       }
-
-       skb_set_inner_protocol(skb, protocol);
-
-       ip6tunnel_xmit(NULL, skb, dev);
-       return 0;
-tx_err_link_failure:
-       stats->tx_carrier_errors++;
-       dst_link_failure(skb);
-tx_err_dst_release:
-       dst_release(dst);
-       return err;
+       return ip6_tnl_xmit(skb, dev, dsfield, fl6, encap_limit, pmtu,
+                           NEXTHDR_GRE);
 }
 
 static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev)
@@ -699,7 +540,6 @@ static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev)
                encap_limit = t->parms.encap_limit;
 
        memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
-       fl6.flowi6_proto = IPPROTO_GRE;
 
        dsfield = ipv4_get_dsfield(iph);
 
@@ -709,7 +549,12 @@ static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev)
        if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
                fl6.flowi6_mark = skb->mark;
 
-       err = ip6gre_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
+       err = gre_handle_offloads(skb, !!(t->parms.o_flags & TUNNEL_CSUM));
+       if (err)
+               return -1;
+
+       err = __gre6_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu,
+                         skb->protocol);
        if (err != 0) {
                /* XXX: send ICMP error even if DF is not set. */
                if (err == -EMSGSIZE)
@@ -749,7 +594,6 @@ static inline int ip6gre_xmit_ipv6(struct sk_buff *skb, struct net_device *dev)
                encap_limit = t->parms.encap_limit;
 
        memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
-       fl6.flowi6_proto = IPPROTO_GRE;
 
        dsfield = ipv6_get_dsfield(ipv6h);
        if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
@@ -759,7 +603,11 @@ static inline int ip6gre_xmit_ipv6(struct sk_buff *skb, struct net_device *dev)
        if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
                fl6.flowi6_mark = skb->mark;
 
-       err = ip6gre_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
+       if (gre_handle_offloads(skb, !!(t->parms.o_flags & TUNNEL_CSUM)))
+               return -1;
+
+       err = __gre6_xmit(skb, dev, dsfield, &fl6, encap_limit,
+                         &mtu, skb->protocol);
        if (err != 0) {
                if (err == -EMSGSIZE)
                        icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
@@ -803,7 +651,11 @@ static int ip6gre_xmit_other(struct sk_buff *skb, struct net_device *dev)
        memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
        fl6.flowi6_proto = skb->protocol;
 
-       err = ip6gre_xmit2(skb, dev, 0, &fl6, encap_limit, &mtu);
+       err = gre_handle_offloads(skb, !!(t->parms.o_flags & TUNNEL_CSUM));
+       if (err)
+               return err;
+
+       err = __gre6_xmit(skb, dev, 0, &fl6, encap_limit, &mtu, skb->protocol);
 
        return err;
 }
@@ -1080,15 +932,6 @@ done:
        return err;
 }
 
-static int ip6gre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
-{
-       if (new_mtu < 68 ||
-           new_mtu > 0xFFF8 - dev->hard_header_len)
-               return -EINVAL;
-       dev->mtu = new_mtu;
-       return 0;
-}
-
 static int ip6gre_header(struct sk_buff *skb, struct net_device *dev,
                        unsigned short type,
                        const void *daddr, const void *saddr, unsigned int len)
@@ -1132,7 +975,7 @@ static const struct net_device_ops ip6gre_netdev_ops = {
        .ndo_uninit             = ip6gre_tunnel_uninit,
        .ndo_start_xmit         = ip6gre_tunnel_xmit,
        .ndo_do_ioctl           = ip6gre_tunnel_ioctl,
-       .ndo_change_mtu         = ip6gre_tunnel_change_mtu,
+       .ndo_change_mtu         = ip6_tnl_change_mtu,
        .ndo_get_stats64        = ip_tunnel_get_stats64,
        .ndo_get_iflink         = ip6_tnl_get_iflink,
 };
@@ -1148,17 +991,11 @@ static void ip6gre_dev_free(struct net_device *dev)
 
 static void ip6gre_tunnel_setup(struct net_device *dev)
 {
-       struct ip6_tnl *t;
-
        dev->netdev_ops = &ip6gre_netdev_ops;
        dev->destructor = ip6gre_dev_free;
 
        dev->type = ARPHRD_IP6GRE;
-       dev->hard_header_len = LL_MAX_HEADER + sizeof(struct ipv6hdr) + 4;
-       dev->mtu = ETH_DATA_LEN - sizeof(struct ipv6hdr) - 4;
-       t = netdev_priv(dev);
-       if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
-               dev->mtu -= 8;
+
        dev->flags |= IFF_NOARP;
        dev->addr_len = sizeof(struct in6_addr);
        netif_keep_dst(dev);
@@ -1168,6 +1005,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
 {
        struct ip6_tnl *tunnel;
        int ret;
+       int t_hlen;
 
        tunnel = netdev_priv(dev);
 
@@ -1186,6 +1024,16 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
                return ret;
        }
 
+       tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
+
+       t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
+
+       dev->needed_headroom    = LL_MAX_HEADER + t_hlen + 4;
+       dev->mtu                = ETH_DATA_LEN - t_hlen - 4;
+
+       if (!(tunnel->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
+               dev->mtu -= 8;
+
        return 0;
 }
 
@@ -1420,7 +1268,7 @@ static const struct net_device_ops ip6gre_tap_netdev_ops = {
        .ndo_start_xmit = ip6gre_tunnel_xmit,
        .ndo_set_mac_address = eth_mac_addr,
        .ndo_validate_addr = eth_validate_addr,
-       .ndo_change_mtu = ip6gre_tunnel_change_mtu,
+       .ndo_change_mtu = ip6_tnl_change_mtu,
        .ndo_get_stats64 = ip_tunnel_get_stats64,
        .ndo_get_iflink = ip6_tnl_get_iflink,
 };