ieee802154: 6lowpan: ensure MTU of 1280 for 6lowpan

This patch drops the userspace accessable sysfs entry for the maximum
datagram size of a 6LoWPAN fragment packet.

A fragment should not have a datagram size value greater than 1280 byte.
Instead of make this value configurable, we accept 1280 datagram size
fragment packets only.

Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/include/net/netns/ieee802154_6lowpan.h b/include/net/netns/ieee802154_6lowpan.h
index e2070960bac009223c1c6caa1324d6323a478a7d..8170f8d7052b21f5b8e82d8cb7c1c52a56042378 100644 (file)
--- a/include/net/netns/ieee802154_6lowpan.h
+++ b/include/net/netns/ieee802154_6lowpan.h
@@ -16,7 +16,6 @@ struct netns_sysctl_lowpan {
 struct netns_ieee802154_lowpan {
        struct netns_sysctl_lowpan sysctl;
        struct netns_frags      frags;
-       int                     max_dsize;
 };
 
 #endif

diff --git a/net/ieee802154/reassembly.c b/net/ieee802154/reassembly.c
index ffec6ce510056960bb92d6ef0c3e44bc9493676f..32755cb7e64e3c02f77c85bdad6982d31311bcc5 100644 (file)
--- a/net/ieee802154/reassembly.c
+++ b/net/ieee802154/reassembly.c
@@ -355,8 +355,6 @@ int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type)
        struct net *net = dev_net(skb->dev);
        struct lowpan_frag_info *frag_info = lowpan_cb(skb);
        struct ieee802154_addr source, dest;
-       struct netns_ieee802154_lowpan *ieee802154_lowpan =
-               net_ieee802154_lowpan(net);
        int err;
 
        source = mac_cb(skb)->source;
@@ -366,8 +364,10 @@ int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type)
        if (err < 0)
                goto err;
 
-       if (frag_info->d_size > ieee802154_lowpan->max_dsize)
+       if (frag_info->d_size > IPV6_MIN_MTU) {
+               net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
                goto err;
+       }
 
        fq = fq_find(net, frag_info, &source, &dest);
        if (fq != NULL) {
@@ -415,13 +415,6 @@ static struct ctl_table lowpan_frags_ns_ctl_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
-       {
-               .procname       = "6lowpanfrag_max_datagram_size",
-               .data           = &init_net.ieee802154_lowpan.max_dsize,
-               .maxlen         = sizeof(int),
-               .mode           = 0644,
-               .proc_handler   = proc_dointvec
-       },
        { }
 };
 
@@ -458,7 +451,6 @@ static int __net_init lowpan_frags_ns_sysctl_register(struct net *net)
                table[1].data = &ieee802154_lowpan->frags.low_thresh;
                table[1].extra2 = &ieee802154_lowpan->frags.high_thresh;
                table[2].data = &ieee802154_lowpan->frags.timeout;
-               table[3].data = &ieee802154_lowpan->max_dsize;
 
                /* Don't export sysctls to unprivileged users */
                if (net->user_ns != &init_user_ns)
@@ -533,7 +525,6 @@ static int __net_init lowpan_frags_init_net(struct net *net)
        ieee802154_lowpan->frags.high_thresh = IPV6_FRAG_HIGH_THRESH;
        ieee802154_lowpan->frags.low_thresh = IPV6_FRAG_LOW_THRESH;
        ieee802154_lowpan->frags.timeout = IPV6_FRAG_TIMEOUT;
-       ieee802154_lowpan->max_dsize = 0xFFFF;
 
        inet_frags_init_net(&ieee802154_lowpan->frags);