[linux-block.git] / net / netfilter / nf_conntrack_seqadj.c

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/types.h>
#include <linux/netfilter.h>
#include <net/tcp.h>

#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_extend.h>
#include <net/netfilter/nf_conntrack_seqadj.h>

int nf_ct_seqadj_init(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
		      s32 off)
{
	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	struct nf_conn_seqadj *seqadj;
	struct nf_ct_seqadj *this_way;

	if (off == 0)
		return 0;

	set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);

	seqadj = nfct_seqadj(ct);
	this_way = &seqadj->seq[dir];
	this_way->offset_before	 = off;
	this_way->offset_after	 = off;
	return 0;
}
EXPORT_SYMBOL_GPL(nf_ct_seqadj_init);

int nf_ct_seqadj_set(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
		     __be32 seq, s32 off)
{
	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	struct nf_ct_seqadj *this_way;

	if (off == 0)
		return 0;

	if (unlikely(!seqadj)) {
		WARN_ONCE(1, "Missing nfct_seqadj_ext_add() setup call\n");
		return 0;
	}

	set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);

	spin_lock_bh(&ct->lock);
	this_way = &seqadj->seq[dir];
	if (this_way->offset_before == this_way->offset_after ||
	    before(this_way->correction_pos, ntohl(seq))) {
		this_way->correction_pos = ntohl(seq);
		this_way->offset_before	 = this_way->offset_after;
		this_way->offset_after	+= off;
	}
	spin_unlock_bh(&ct->lock);
	return 0;
}
EXPORT_SYMBOL_GPL(nf_ct_seqadj_set);

void nf_ct_tcp_seqadj_set(struct sk_buff *skb,
			  struct nf_conn *ct, enum ip_conntrack_info ctinfo,
			  s32 off)
{
	const struct tcphdr *th;

	if (nf_ct_protonum(ct) != IPPROTO_TCP)
		return;

	th = (struct tcphdr *)(skb_network_header(skb) + ip_hdrlen(skb));
	nf_ct_seqadj_set(ct, ctinfo, th->seq, off);
}
EXPORT_SYMBOL_GPL(nf_ct_tcp_seqadj_set);

/* Adjust one found SACK option including checksum correction */
static void nf_ct_sack_block_adjust(struct sk_buff *skb,
				    struct tcphdr *tcph,
				    unsigned int sackoff,
				    unsigned int sackend,
				    struct nf_ct_seqadj *seq)
{
	while (sackoff < sackend) {
		struct tcp_sack_block_wire *sack;
		__be32 new_start_seq, new_end_seq;

		sack = (void *)skb->data + sackoff;
		if (after(ntohl(sack->start_seq) - seq->offset_before,
			  seq->correction_pos))
			new_start_seq = htonl(ntohl(sack->start_seq) -
					seq->offset_after);
		else
			new_start_seq = htonl(ntohl(sack->start_seq) -
					seq->offset_before);

		if (after(ntohl(sack->end_seq) - seq->offset_before,
			  seq->correction_pos))
			new_end_seq = htonl(ntohl(sack->end_seq) -
				      seq->offset_after);
		else
			new_end_seq = htonl(ntohl(sack->end_seq) -
				      seq->offset_before);

		pr_debug("sack_adjust: start_seq: %u->%u, end_seq: %u->%u\n",
			 ntohl(sack->start_seq), ntohl(new_start_seq),
			 ntohl(sack->end_seq), ntohl(new_end_seq));

		inet_proto_csum_replace4(&tcph->check, skb,
					 sack->start_seq, new_start_seq, false);
		inet_proto_csum_replace4(&tcph->check, skb,
					 sack->end_seq, new_end_seq, false);
		sack->start_seq = new_start_seq;
		sack->end_seq = new_end_seq;
		sackoff += sizeof(*sack);
	}
}

/* TCP SACK sequence number adjustment */
static unsigned int nf_ct_sack_adjust(struct sk_buff *skb,
				      unsigned int protoff,
				      struct nf_conn *ct,
				      enum ip_conntrack_info ctinfo)
{
	struct tcphdr *tcph = (void *)skb->data + protoff;
	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
	unsigned int dir, optoff, optend;

	optoff = protoff + sizeof(struct tcphdr);
	optend = protoff + tcph->doff * 4;

	if (skb_ensure_writable(skb, optend))
		return 0;

	tcph = (void *)skb->data + protoff;
	dir = CTINFO2DIR(ctinfo);

	while (optoff < optend) {
		/* Usually: option, length. */
		unsigned char *op = skb->data + optoff;

		switch (op[0]) {
		case TCPOPT_EOL:
			return 1;
		case TCPOPT_NOP:
			optoff++;
			continue;
		default:
			/* no partial options */
			if (optoff + 1 == optend ||
			    optoff + op[1] > optend ||
			    op[1] < 2)
				return 0;
			if (op[0] == TCPOPT_SACK &&
			    op[1] >= 2+TCPOLEN_SACK_PERBLOCK &&
			    ((op[1] - 2) % TCPOLEN_SACK_PERBLOCK) == 0)
				nf_ct_sack_block_adjust(skb, tcph, optoff + 2,
							optoff+op[1],
							&seqadj->seq[!dir]);
			optoff += op[1];
		}
	}
	return 1;
}

/* TCP sequence number adjustment.  Returns 1 on success, 0 on failure */
int nf_ct_seq_adjust(struct sk_buff *skb,
		     struct nf_conn *ct, enum ip_conntrack_info ctinfo,
		     unsigned int protoff)
{
	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	struct tcphdr *tcph;
	__be32 newseq, newack;
	s32 seqoff, ackoff;
	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
	struct nf_ct_seqadj *this_way, *other_way;
	int res = 1;

	this_way  = &seqadj->seq[dir];
	other_way = &seqadj->seq[!dir];

	if (skb_ensure_writable(skb, protoff + sizeof(*tcph)))
		return 0;

	tcph = (void *)skb->data + protoff;
	spin_lock_bh(&ct->lock);
	if (after(ntohl(tcph->seq), this_way->correction_pos))
		seqoff = this_way->offset_after;
	else
		seqoff = this_way->offset_before;

	newseq = htonl(ntohl(tcph->seq) + seqoff);
	inet_proto_csum_replace4(&tcph->check, skb, tcph->seq, newseq, false);
	pr_debug("Adjusting sequence number from %u->%u\n",
		 ntohl(tcph->seq), ntohl(newseq));
	tcph->seq = newseq;

	if (!tcph->ack)
		goto out;

	if (after(ntohl(tcph->ack_seq) - other_way->offset_before,
		  other_way->correction_pos))
		ackoff = other_way->offset_after;
	else
		ackoff = other_way->offset_before;

	newack = htonl(ntohl(tcph->ack_seq) - ackoff);
	inet_proto_csum_replace4(&tcph->check, skb, tcph->ack_seq, newack,
				 false);
	pr_debug("Adjusting ack number from %u->%u, ack from %u->%u\n",
		 ntohl(tcph->seq), ntohl(newseq), ntohl(tcph->ack_seq),
		 ntohl(newack));
	tcph->ack_seq = newack;

	res = nf_ct_sack_adjust(skb, protoff, ct, ctinfo);
out:
	spin_unlock_bh(&ct->lock);

	return res;
}
EXPORT_SYMBOL_GPL(nf_ct_seq_adjust);

s32 nf_ct_seq_offset(const struct nf_conn *ct,
		     enum ip_conntrack_dir dir,
		     u32 seq)
{
	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
	struct nf_ct_seqadj *this_way;

	if (!seqadj)
		return 0;

	this_way = &seqadj->seq[dir];
	return after(seq, this_way->correction_pos) ?
		 this_way->offset_after : this_way->offset_before;
}
EXPORT_SYMBOL_GPL(nf_ct_seq_offset);
Commit	Line	Data
457c8996	1	// SPDX-License-Identifier: GPL-2.0-only
41d73ec0 PM	2	#include <linux/types.h>
	3	#include <linux/netfilter.h>
	4	#include <net/tcp.h>
	5
	6	#include <net/netfilter/nf_conntrack.h>
	7	#include <net/netfilter/nf_conntrack_extend.h>
	8	#include <net/netfilter/nf_conntrack_seqadj.h>
	9
48b1de4c PM	10	int nf_ct_seqadj_init(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
	11	s32 off)
	12	{
	13	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	14	struct nf_conn_seqadj *seqadj;
	15	struct nf_ct_seqadj *this_way;
	16
	17	if (off == 0)
	18	return 0;
	19
	20	set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
	21
	22	seqadj = nfct_seqadj(ct);
	23	this_way = &seqadj->seq[dir];
	24	this_way->offset_before = off;
	25	this_way->offset_after = off;
	26	return 0;
	27	}
	28	EXPORT_SYMBOL_GPL(nf_ct_seqadj_init);
	29
41d73ec0 PM	30	int nf_ct_seqadj_set(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
	31	__be32 seq, s32 off)
	32	{
	33	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
	34	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	35	struct nf_ct_seqadj *this_way;
	36
	37	if (off == 0)
	38	return 0;
	39
db12cf27	40	if (unlikely(!seqadj)) {
f2661adc	41	WARN_ONCE(1, "Missing nfct_seqadj_ext_add() setup call\n");
db12cf27 JDB	42	return 0;
	43	}
	44
41d73ec0 PM	45	set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
	46
	47	spin_lock_bh(&ct->lock);
	48	this_way = &seqadj->seq[dir];
	49	if (this_way->offset_before == this_way->offset_after \|\|
23dfe136 PO	50	before(this_way->correction_pos, ntohl(seq))) {
23dfe136 PO	51	this_way->correction_pos = ntohl(seq);
41d73ec0 PM	52	this_way->offset_before = this_way->offset_after;
	53	this_way->offset_after += off;
	54	}
	55	spin_unlock_bh(&ct->lock);
	56	return 0;
	57	}
	58	EXPORT_SYMBOL_GPL(nf_ct_seqadj_set);
	59
	60	void nf_ct_tcp_seqadj_set(struct sk_buff *skb,
	61	struct nf_conn *ct, enum ip_conntrack_info ctinfo,
	62	s32 off)
	63	{
	64	const struct tcphdr *th;
	65
	66	if (nf_ct_protonum(ct) != IPPROTO_TCP)
	67	return;
	68
	69	th = (struct tcphdr *)(skb_network_header(skb) + ip_hdrlen(skb));
	70	nf_ct_seqadj_set(ct, ctinfo, th->seq, off);
	71	}
	72	EXPORT_SYMBOL_GPL(nf_ct_tcp_seqadj_set);
	73
	74	/* Adjust one found SACK option including checksum correction */
	75	static void nf_ct_sack_block_adjust(struct sk_buff *skb,
	76	struct tcphdr *tcph,
	77	unsigned int sackoff,
	78	unsigned int sackend,
	79	struct nf_ct_seqadj *seq)
	80	{
	81	while (sackoff < sackend) {
	82	struct tcp_sack_block_wire *sack;
	83	__be32 new_start_seq, new_end_seq;
	84
	85	sack = (void *)skb->data + sackoff;
	86	if (after(ntohl(sack->start_seq) - seq->offset_before,
	87	seq->correction_pos))
	88	new_start_seq = htonl(ntohl(sack->start_seq) -
	89	seq->offset_after);
	90	else
	91	new_start_seq = htonl(ntohl(sack->start_seq) -
	92	seq->offset_before);
	93
	94	if (after(ntohl(sack->end_seq) - seq->offset_before,
	95	seq->correction_pos))
	96	new_end_seq = htonl(ntohl(sack->end_seq) -
	97	seq->offset_after);
	98	else
	99	new_end_seq = htonl(ntohl(sack->end_seq) -
	100	seq->offset_before);
	101
b44b565c G	102	pr_debug("sack_adjust: start_seq: %u->%u, end_seq: %u->%u\n",
	103	ntohl(sack->start_seq), ntohl(new_start_seq),
	104	ntohl(sack->end_seq), ntohl(new_end_seq));
41d73ec0 PM	105
41d73ec0 PM	106	inet_proto_csum_replace4(&tcph->check, skb,
4b048d6d	107	sack->start_seq, new_start_seq, false);
41d73ec0	108	inet_proto_csum_replace4(&tcph->check, skb,
4b048d6d	109	sack->end_seq, new_end_seq, false);
41d73ec0 PM	110	sack->start_seq = new_start_seq;
	111	sack->end_seq = new_end_seq;
	112	sackoff += sizeof(*sack);
	113	}
	114	}
	115
	116	/* TCP SACK sequence number adjustment */
	117	static unsigned int nf_ct_sack_adjust(struct sk_buff *skb,
	118	unsigned int protoff,
41d73ec0 PM	119	struct nf_conn *ct,
	120	enum ip_conntrack_info ctinfo)
	121	{
530aad77	122	struct tcphdr tcph = (void )skb->data + protoff;
41d73ec0	123	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
530aad77	124	unsigned int dir, optoff, optend;
41d73ec0 PM	125
	126	optoff = protoff + sizeof(struct tcphdr);
	127	optend = protoff + tcph->doff * 4;
	128
86f04538	129	if (skb_ensure_writable(skb, optend))
41d73ec0 PM	130	return 0;
41d73ec0 PM	131
530aad77	132	tcph = (void *)skb->data + protoff;
41d73ec0 PM	133	dir = CTINFO2DIR(ctinfo);
	134
	135	while (optoff < optend) {
	136	/* Usually: option, length. */
	137	unsigned char *op = skb->data + optoff;
	138
	139	switch (op[0]) {
	140	case TCPOPT_EOL:
	141	return 1;
	142	case TCPOPT_NOP:
	143	optoff++;
	144	continue;
	145	default:
	146	/* no partial options */
	147	if (optoff + 1 == optend \|\|
	148	optoff + op[1] > optend \|\|
	149	op[1] < 2)
	150	return 0;
	151	if (op[0] == TCPOPT_SACK &&
	152	op[1] >= 2+TCPOLEN_SACK_PERBLOCK &&
	153	((op[1] - 2) % TCPOLEN_SACK_PERBLOCK) == 0)
	154	nf_ct_sack_block_adjust(skb, tcph, optoff + 2,
	155	optoff+op[1],
	156	&seqadj->seq[!dir]);
	157	optoff += op[1];
	158	}
	159	}
	160	return 1;
	161	}
	162
	163	/* TCP sequence number adjustment. Returns 1 on success, 0 on failure */
	164	int nf_ct_seq_adjust(struct sk_buff *skb,
	165	struct nf_conn *ct, enum ip_conntrack_info ctinfo,
	166	unsigned int protoff)
	167	{
	168	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	169	struct tcphdr *tcph;
	170	__be32 newseq, newack;
	171	s32 seqoff, ackoff;
	172	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
	173	struct nf_ct_seqadj this_way, other_way;
8d11350f	174	int res = 1;
41d73ec0 PM	175
	176	this_way = &seqadj->seq[dir];
	177	other_way = &seqadj->seq[!dir];
	178
86f04538	179	if (skb_ensure_writable(skb, protoff + sizeof(*tcph)))
41d73ec0 PM	180	return 0;
	181
	182	tcph = (void *)skb->data + protoff;
	183	spin_lock_bh(&ct->lock);
	184	if (after(ntohl(tcph->seq), this_way->correction_pos))
	185	seqoff = this_way->offset_after;
	186	else
	187	seqoff = this_way->offset_before;
	188
8d11350f GF	189	newseq = htonl(ntohl(tcph->seq) + seqoff);
	190	inet_proto_csum_replace4(&tcph->check, skb, tcph->seq, newseq, false);
	191	pr_debug("Adjusting sequence number from %u->%u\n",
	192	ntohl(tcph->seq), ntohl(newseq));
	193	tcph->seq = newseq;
	194
	195	if (!tcph->ack)
	196	goto out;
	197
41d73ec0 PM	198	if (after(ntohl(tcph->ack_seq) - other_way->offset_before,
	199	other_way->correction_pos))
	200	ackoff = other_way->offset_after;
	201	else
	202	ackoff = other_way->offset_before;
	203
41d73ec0	204	newack = htonl(ntohl(tcph->ack_seq) - ackoff);
4b048d6d TH	205	inet_proto_csum_replace4(&tcph->check, skb, tcph->ack_seq, newack,
4b048d6d TH	206	false);
8d11350f	207	pr_debug("Adjusting ack number from %u->%u, ack from %u->%u\n",
41d73ec0 PM	208	ntohl(tcph->seq), ntohl(newseq), ntohl(tcph->ack_seq),
41d73ec0 PM	209	ntohl(newack));
41d73ec0 PM	210	tcph->ack_seq = newack;
41d73ec0 PM	211
530aad77	212	res = nf_ct_sack_adjust(skb, protoff, ct, ctinfo);
8d11350f	213	out:
41d73ec0 PM	214	spin_unlock_bh(&ct->lock);
	215
	216	return res;
	217	}
	218	EXPORT_SYMBOL_GPL(nf_ct_seq_adjust);
	219
	220	s32 nf_ct_seq_offset(const struct nf_conn *ct,
	221	enum ip_conntrack_dir dir,
	222	u32 seq)
	223	{
	224	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
	225	struct nf_ct_seqadj *this_way;
	226
	227	if (!seqadj)
	228	return 0;
	229
	230	this_way = &seqadj->seq[dir];
	231	return after(seq, this_way->correction_pos) ?
	232	this_way->offset_after : this_way->offset_before;
	233	}
	234	EXPORT_SYMBOL_GPL(nf_ct_seq_offset);