1
2#include <net/netlink.h>
3#include <net/sch_generic.h>
4#include <net/dst.h>
5#include <net/ip.h>
6#include <net/ip6_fib.h>
7
8struct sch_frag_data {
9 unsigned long dst;
10 struct qdisc_skb_cb cb;
11 __be16 inner_protocol;
12 u16 vlan_tci;
13 __be16 vlan_proto;
14 unsigned int l2_len;
15 u8 l2_data[VLAN_ETH_HLEN];
16 int (*xmit)(struct sk_buff *skb);
17};
18
19static DEFINE_PER_CPU(struct sch_frag_data, sch_frag_data_storage);
20
21static int sch_frag_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
22{
23 struct sch_frag_data *data = this_cpu_ptr(&sch_frag_data_storage);
24
25 if (skb_cow_head(skb, data->l2_len) < 0) {
26 kfree_skb(skb);
27 return -ENOMEM;
28 }
29
30 __skb_dst_copy(skb, data->dst);
31 *qdisc_skb_cb(skb) = data->cb;
32 skb->inner_protocol = data->inner_protocol;
33 if (data->vlan_tci & VLAN_CFI_MASK)
34 __vlan_hwaccel_put_tag(skb, data->vlan_proto,
35 data->vlan_tci & ~VLAN_CFI_MASK);
36 else
37 __vlan_hwaccel_clear_tag(skb);
38
39
40 skb_push(skb, data->l2_len);
41 memcpy(skb->data, &data->l2_data, data->l2_len);
42 skb_postpush_rcsum(skb, skb->data, data->l2_len);
43 skb_reset_mac_header(skb);
44
45 return data->xmit(skb);
46}
47
48static void sch_frag_prepare_frag(struct sk_buff *skb,
49 int (*xmit)(struct sk_buff *skb))
50{
51 unsigned int hlen = skb_network_offset(skb);
52 struct sch_frag_data *data;
53
54 data = this_cpu_ptr(&sch_frag_data_storage);
55 data->dst = skb->_skb_refdst;
56 data->cb = *qdisc_skb_cb(skb);
57 data->xmit = xmit;
58 data->inner_protocol = skb->inner_protocol;
59 if (skb_vlan_tag_present(skb))
60 data->vlan_tci = skb_vlan_tag_get(skb) | VLAN_CFI_MASK;
61 else
62 data->vlan_tci = 0;
63 data->vlan_proto = skb->vlan_proto;
64 data->l2_len = hlen;
65 memcpy(&data->l2_data, skb->data, hlen);
66
67 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
68 skb_pull(skb, hlen);
69}
70
71static unsigned int
72sch_frag_dst_get_mtu(const struct dst_entry *dst)
73{
74 return dst->dev->mtu;
75}
76
77static struct dst_ops sch_frag_dst_ops = {
78 .family = AF_UNSPEC,
79 .mtu = sch_frag_dst_get_mtu,
80};
81
82static int sch_fragment(struct net *net, struct sk_buff *skb,
83 u16 mru, int (*xmit)(struct sk_buff *skb))
84{
85 int ret = -1;
86
87 if (skb_network_offset(skb) > VLAN_ETH_HLEN) {
88 net_warn_ratelimited("L2 header too long to fragment\n");
89 goto err;
90 }
91
92 if (skb_protocol(skb, true) == htons(ETH_P_IP)) {
93 struct rtable sch_frag_rt = { 0 };
94 unsigned long orig_dst;
95
96 sch_frag_prepare_frag(skb, xmit);
97 dst_init(&sch_frag_rt.dst, &sch_frag_dst_ops, NULL, 1,
98 DST_OBSOLETE_NONE, DST_NOCOUNT);
99 sch_frag_rt.dst.dev = skb->dev;
100
101 orig_dst = skb->_skb_refdst;
102 skb_dst_set_noref(skb, &sch_frag_rt.dst);
103 IPCB(skb)->frag_max_size = mru;
104
105 ret = ip_do_fragment(net, skb->sk, skb, sch_frag_xmit);
106 refdst_drop(orig_dst);
107 } else if (skb_protocol(skb, true) == htons(ETH_P_IPV6)) {
108 unsigned long orig_dst;
109 struct rt6_info sch_frag_rt;
110
111 sch_frag_prepare_frag(skb, xmit);
112 memset(&sch_frag_rt, 0, sizeof(sch_frag_rt));
113 dst_init(&sch_frag_rt.dst, &sch_frag_dst_ops, NULL, 1,
114 DST_OBSOLETE_NONE, DST_NOCOUNT);
115 sch_frag_rt.dst.dev = skb->dev;
116
117 orig_dst = skb->_skb_refdst;
118 skb_dst_set_noref(skb, &sch_frag_rt.dst);
119 IP6CB(skb)->frag_max_size = mru;
120
121 ret = ipv6_stub->ipv6_fragment(net, skb->sk, skb,
122 sch_frag_xmit);
123 refdst_drop(orig_dst);
124 } else {
125 net_warn_ratelimited("Fail frag %s: eth=%x, MRU=%d, MTU=%d\n",
126 netdev_name(skb->dev),
127 ntohs(skb_protocol(skb, true)), mru,
128 skb->dev->mtu);
129 goto err;
130 }
131
132 return ret;
133err:
134 kfree_skb(skb);
135 return ret;
136}
137
138int sch_frag_xmit_hook(struct sk_buff *skb, int (*xmit)(struct sk_buff *skb))
139{
140 u16 mru = qdisc_skb_cb(skb)->mru;
141 int err;
142
143 if (mru && skb->len > mru + skb->dev->hard_header_len)
144 err = sch_fragment(dev_net(skb->dev), skb, mru, xmit);
145 else
146 err = xmit(skb);
147
148 return err;
149}
150EXPORT_SYMBOL_GPL(sch_frag_xmit_hook);
151
