[linux.git] / net / sched / sch_frag.c

// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
#include <net/netlink.h>
#include <net/sch_generic.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/ip6_fib.h>

struct sch_frag_data {
	unsigned long dst;
	struct qdisc_skb_cb cb;
	__be16 inner_protocol;
	u16 vlan_tci;
	__be16 vlan_proto;
	unsigned int l2_len;
	u8 l2_data[VLAN_ETH_HLEN];
	int (*xmit)(struct sk_buff *skb);
};

static DEFINE_PER_CPU(struct sch_frag_data, sch_frag_data_storage);

static int sch_frag_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct sch_frag_data *data = this_cpu_ptr(&sch_frag_data_storage);

	if (skb_cow_head(skb, data->l2_len) < 0) {
		kfree_skb(skb);
		return -ENOMEM;
	}

	__skb_dst_copy(skb, data->dst);
	*qdisc_skb_cb(skb) = data->cb;
	skb->inner_protocol = data->inner_protocol;
	if (data->vlan_tci & VLAN_CFI_MASK)
		__vlan_hwaccel_put_tag(skb, data->vlan_proto,
				       data->vlan_tci & ~VLAN_CFI_MASK);
	else
		__vlan_hwaccel_clear_tag(skb);

	/* Reconstruct the MAC header.  */
	skb_push(skb, data->l2_len);
	memcpy(skb->data, &data->l2_data, data->l2_len);
	skb_postpush_rcsum(skb, skb->data, data->l2_len);
	skb_reset_mac_header(skb);

	return data->xmit(skb);
}

static void sch_frag_prepare_frag(struct sk_buff *skb,
				  int (*xmit)(struct sk_buff *skb))
{
	unsigned int hlen = skb_network_offset(skb);
	struct sch_frag_data *data;

	data = this_cpu_ptr(&sch_frag_data_storage);
	data->dst = skb->_skb_refdst;
	data->cb = *qdisc_skb_cb(skb);
	data->xmit = xmit;
	data->inner_protocol = skb->inner_protocol;
	if (skb_vlan_tag_present(skb))
		data->vlan_tci = skb_vlan_tag_get(skb) | VLAN_CFI_MASK;
	else
		data->vlan_tci = 0;
	data->vlan_proto = skb->vlan_proto;
	data->l2_len = hlen;
	memcpy(&data->l2_data, skb->data, hlen);

	memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
	skb_pull(skb, hlen);
}

static unsigned int
sch_frag_dst_get_mtu(const struct dst_entry *dst)
{
	return dst->dev->mtu;
}

static struct dst_ops sch_frag_dst_ops = {
	.family = AF_UNSPEC,
	.mtu = sch_frag_dst_get_mtu,
};

static int sch_fragment(struct net *net, struct sk_buff *skb,
			u16 mru, int (*xmit)(struct sk_buff *skb))
{
	int ret = -1;

	if (skb_network_offset(skb) > VLAN_ETH_HLEN) {
		net_warn_ratelimited("L2 header too long to fragment\n");
		goto err;
	}

	if (skb_protocol(skb, true) == htons(ETH_P_IP)) {
		struct dst_entry sch_frag_dst;
		unsigned long orig_dst;

		sch_frag_prepare_frag(skb, xmit);
		dst_init(&sch_frag_dst, &sch_frag_dst_ops, NULL, 1,
			 DST_OBSOLETE_NONE, DST_NOCOUNT);
		sch_frag_dst.dev = skb->dev;

		orig_dst = skb->_skb_refdst;
		skb_dst_set_noref(skb, &sch_frag_dst);
		IPCB(skb)->frag_max_size = mru;

		ret = ip_do_fragment(net, skb->sk, skb, sch_frag_xmit);
		refdst_drop(orig_dst);
	} else if (skb_protocol(skb, true) == htons(ETH_P_IPV6)) {
		unsigned long orig_dst;
		struct rt6_info sch_frag_rt;

		sch_frag_prepare_frag(skb, xmit);
		memset(&sch_frag_rt, 0, sizeof(sch_frag_rt));
		dst_init(&sch_frag_rt.dst, &sch_frag_dst_ops, NULL, 1,
			 DST_OBSOLETE_NONE, DST_NOCOUNT);
		sch_frag_rt.dst.dev = skb->dev;

		orig_dst = skb->_skb_refdst;
		skb_dst_set_noref(skb, &sch_frag_rt.dst);
		IP6CB(skb)->frag_max_size = mru;

		ret = ipv6_stub->ipv6_fragment(net, skb->sk, skb,
					       sch_frag_xmit);
		refdst_drop(orig_dst);
	} else {
		net_warn_ratelimited("Fail frag %s: eth=%x, MRU=%d, MTU=%d\n",
				     netdev_name(skb->dev),
				     ntohs(skb_protocol(skb, true)), mru,
				     skb->dev->mtu);
		goto err;
	}

	return ret;
err:
	kfree_skb(skb);
	return ret;
}

int sch_frag_xmit_hook(struct sk_buff *skb, int (*xmit)(struct sk_buff *skb))
{
	u16 mru = qdisc_skb_cb(skb)->mru;
	int err;

	if (mru && skb->len > mru + skb->dev->hard_header_len)
		err = sch_fragment(dev_net(skb->dev), skb, mru, xmit);
	else
		err = xmit(skb);

	return err;
}
EXPORT_SYMBOL_GPL(sch_frag_xmit_hook);
Commit	Line	Data
c129412f	1	// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
	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
	8	struct 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
	19	static DEFINE_PER_CPU(struct sch_frag_data, sch_frag_data_storage);
	20
	21	static 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	/* Reconstruct the MAC header. */
	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
	48	static 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
71	static unsigned int
72	sch_frag_dst_get_mtu(const struct dst_entry *dst)
73	{
74	return dst->dev->mtu;
75	}
76
77	static struct dst_ops sch_frag_dst_ops = {
78	.family = AF_UNSPEC,
79	.mtu = sch_frag_dst_get_mtu,
80	};
81
82	static 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 dst_entry sch_frag_dst;
94	unsigned long orig_dst;
95
96	sch_frag_prepare_frag(skb, xmit);
97	dst_init(&sch_frag_dst, &sch_frag_dst_ops, NULL, 1,
98	DST_OBSOLETE_NONE, DST_NOCOUNT);
99	sch_frag_dst.dev = skb->dev;
100
101	orig_dst = skb->_skb_refdst;
102	skb_dst_set_noref(skb, &sch_frag_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;
133	err:
134	kfree_skb(skb);
135	return ret;
136	}
137
138	int 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	}
150	EXPORT_SYMBOL_GPL(sch_frag_xmit_hook);