// SPDX-License-Identifier: GPL-2.0

  /*
   * xfrm_input.c
   *
   * Changes:
   * 	YOSHIFUJI Hideaki @USAGI
   * 		Split up af-specific portion

   *

   */

  #include <linux/bottom_half.h>
  #include <linux/interrupt.h>

  #include <linux/slab.h>
  #include <linux/module.h>

  #include <linux/netdevice.h>

  #include <linux/percpu.h>

  #include <net/dst.h>

  #include <net/ip.h>
  #include <net/xfrm.h>

  #include <net/ip_tunnels.h>
  #include <net/ip6_tunnel.h>

  struct xfrm_trans_tasklet {
  	struct tasklet_struct tasklet;
  	struct sk_buff_head queue;
  };
  
  struct xfrm_trans_cb {

  	union {
  		struct inet_skb_parm	h4;
  #if IS_ENABLED(CONFIG_IPV6)
  		struct inet6_skb_parm	h6;
  #endif
  	} header;

  	int (*finish)(struct net *net, struct sock *sk, struct sk_buff *skb);
  };
  
  #define XFRM_TRANS_SKB_CB(__skb) ((struct xfrm_trans_cb *)&((__skb)->cb[0]))

  static struct kmem_cache *secpath_cachep __read_mostly;

  static DEFINE_SPINLOCK(xfrm_input_afinfo_lock);

  static struct xfrm_input_afinfo const __rcu *xfrm_input_afinfo[AF_INET6 + 1];

  static struct gro_cells gro_cells;
  static struct net_device xfrm_napi_dev;

  static DEFINE_PER_CPU(struct xfrm_trans_tasklet, xfrm_trans_tasklet);

  int xfrm_input_register_afinfo(const struct xfrm_input_afinfo *afinfo)

  {
  	int err = 0;

  	if (WARN_ON(afinfo->family >= ARRAY_SIZE(xfrm_input_afinfo)))

  		return -EAFNOSUPPORT;

  	spin_lock_bh(&xfrm_input_afinfo_lock);
  	if (unlikely(xfrm_input_afinfo[afinfo->family] != NULL))

  		err = -EEXIST;

  	else
  		rcu_assign_pointer(xfrm_input_afinfo[afinfo->family], afinfo);
  	spin_unlock_bh(&xfrm_input_afinfo_lock);
  	return err;
  }
  EXPORT_SYMBOL(xfrm_input_register_afinfo);

  int xfrm_input_unregister_afinfo(const struct xfrm_input_afinfo *afinfo)

  {
  	int err = 0;

  	spin_lock_bh(&xfrm_input_afinfo_lock);
  	if (likely(xfrm_input_afinfo[afinfo->family] != NULL)) {
  		if (unlikely(xfrm_input_afinfo[afinfo->family] != afinfo))
  			err = -EINVAL;
  		else
  			RCU_INIT_POINTER(xfrm_input_afinfo[afinfo->family], NULL);
  	}
  	spin_unlock_bh(&xfrm_input_afinfo_lock);
  	synchronize_rcu();
  	return err;
  }
  EXPORT_SYMBOL(xfrm_input_unregister_afinfo);

  static const struct xfrm_input_afinfo *xfrm_input_get_afinfo(unsigned int family)

  {

  	const struct xfrm_input_afinfo *afinfo;

  	if (WARN_ON_ONCE(family >= ARRAY_SIZE(xfrm_input_afinfo)))

  		return NULL;

  	rcu_read_lock();
  	afinfo = rcu_dereference(xfrm_input_afinfo[family]);
  	if (unlikely(!afinfo))
  		rcu_read_unlock();
  	return afinfo;
  }

  static int xfrm_rcv_cb(struct sk_buff *skb, unsigned int family, u8 protocol,
  		       int err)
  {
  	int ret;

  	const struct xfrm_input_afinfo *afinfo = xfrm_input_get_afinfo(family);

  
  	if (!afinfo)
  		return -EAFNOSUPPORT;
  
  	ret = afinfo->callback(skb, protocol, err);

  	rcu_read_unlock();

  
  	return ret;
  }

  void __secpath_destroy(struct sec_path *sp)
  {
  	int i;
  	for (i = 0; i < sp->len; i++)

  		xfrm_state_put(sp->xvec[i]);

  	kmem_cache_free(secpath_cachep, sp);
  }
  EXPORT_SYMBOL(__secpath_destroy);
  
  struct sec_path *secpath_dup(struct sec_path *src)
  {
  	struct sec_path *sp;

  	sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC);

  	if (!sp)
  		return NULL;
  
  	sp->len = 0;

  	sp->olen = 0;

  	memset(sp->ovec, 0, sizeof(sp->ovec[XFRM_MAX_OFFLOAD_DEPTH]));

  	if (src) {
  		int i;
  
  		memcpy(sp, src, sizeof(*sp));
  		for (i = 0; i < sp->len; i++)

  			xfrm_state_hold(sp->xvec[i]);

  	}

  	refcount_set(&sp->refcnt, 1);

  	return sp;
  }
  EXPORT_SYMBOL(secpath_dup);

  int secpath_set(struct sk_buff *skb)
  {
  	struct sec_path *sp;
  
  	/* Allocate new secpath or COW existing one. */

  	if (!skb->sp || refcount_read(&skb->sp->refcnt) != 1) {

  		sp = secpath_dup(skb->sp);
  		if (!sp)
  			return -ENOMEM;
  
  		if (skb->sp)
  			secpath_put(skb->sp);
  		skb->sp = sp;
  	}
  	return 0;
  }
  EXPORT_SYMBOL(secpath_set);

  /* Fetch spi and seq from ipsec header */

  int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)

  {
  	int offset, offset_seq;

  	int hlen;

  
  	switch (nexthdr) {
  	case IPPROTO_AH:

  		hlen = sizeof(struct ip_auth_hdr);

  		offset = offsetof(struct ip_auth_hdr, spi);
  		offset_seq = offsetof(struct ip_auth_hdr, seq_no);
  		break;
  	case IPPROTO_ESP:

  		hlen = sizeof(struct ip_esp_hdr);

  		offset = offsetof(struct ip_esp_hdr, spi);
  		offset_seq = offsetof(struct ip_esp_hdr, seq_no);
  		break;
  	case IPPROTO_COMP:
  		if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
  			return -EINVAL;

  		*spi = htonl(ntohs(*(__be16 *)(skb_transport_header(skb) + 2)));

  		*seq = 0;
  		return 0;
  	default:
  		return 1;
  	}

  	if (!pskb_may_pull(skb, hlen))

  		return -EINVAL;

  	*spi = *(__be32 *)(skb_transport_header(skb) + offset);
  	*seq = *(__be32 *)(skb_transport_header(skb) + offset_seq);

  	return 0;
  }

  EXPORT_SYMBOL(xfrm_parse_spi);

  int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
  {

  	struct xfrm_mode *inner_mode = x->inner_mode;

  	int err;
  
  	err = x->outer_mode->afinfo->extract_input(x, skb);
  	if (err)
  		return err;

  	if (x->sel.family == AF_UNSPEC) {
  		inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
  		if (inner_mode == NULL)
  			return -EAFNOSUPPORT;
  	}
  
  	skb->protocol = inner_mode->afinfo->eth_proto;
  	return inner_mode->input2(x, skb);

  }
  EXPORT_SYMBOL(xfrm_prepare_input);

  int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
  {

  	struct net *net = dev_net(skb->dev);

  	int err;
  	__be32 seq;

  	__be32 seq_hi;

  	struct xfrm_state *x = NULL;

  	xfrm_address_t *daddr;

  	struct xfrm_mode *inner_mode;

  	u32 mark = skb->mark;

  	unsigned int family = AF_UNSPEC;

  	int decaps = 0;

  	int async = 0;

  	bool xfrm_gro = false;

  	bool crypto_done = false;
  	struct xfrm_offload *xo = xfrm_offload(skb);

  	if (encap_type < 0) {

  		x = xfrm_input_state(skb);

  
  		if (unlikely(x->km.state != XFRM_STATE_VALID)) {
  			if (x->km.state == XFRM_STATE_ACQ)
  				XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
  			else
  				XFRM_INC_STATS(net,
  					       LINUX_MIB_XFRMINSTATEINVALID);
  			goto drop;
  		}

  		family = x->outer_mode->afinfo->family;

  
  		/* An encap_type of -1 indicates async resumption. */
  		if (encap_type == -1) {
  			async = 1;
  			seq = XFRM_SKB_CB(skb)->seq.input.low;
  			goto resume;
  		}

  		/* encap_type < -1 indicates a GRO call. */
  		encap_type = 0;
  		seq = XFRM_SPI_SKB_CB(skb)->seq;

  		if (xo && (xo->flags & CRYPTO_DONE)) {
  			crypto_done = true;
  			x = xfrm_input_state(skb);
  			family = XFRM_SPI_SKB_CB(skb)->family;
  
  			if (!(xo->status & CRYPTO_SUCCESS)) {
  				if (xo->status &
  				    (CRYPTO_TRANSPORT_AH_AUTH_FAILED |
  				     CRYPTO_TRANSPORT_ESP_AUTH_FAILED |
  				     CRYPTO_TUNNEL_AH_AUTH_FAILED |
  				     CRYPTO_TUNNEL_ESP_AUTH_FAILED)) {
  
  					xfrm_audit_state_icvfail(x, skb,
  								 x->type->proto);
  					x->stats.integrity_failed++;
  					XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
  					goto drop;
  				}

  				if (xo->status & CRYPTO_INVALID_PROTOCOL) {
  					XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
  					goto drop;
  				}

  				XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);

  				goto drop;
  			}

  			if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
  				XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
  				goto drop;
  			}

  		}

  		goto lock;

  	}

  	family = XFRM_SPI_SKB_CB(skb)->family;

  	/* if tunnel is present override skb->mark value with tunnel i_key */

  	switch (family) {
  	case AF_INET:
  		if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4)

  			mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4->parms.i_key);

  		break;
  	case AF_INET6:
  		if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6)

  			mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6->parms.i_key);

  		break;

  	}

  	err = secpath_set(skb);
  	if (err) {
  		XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
  		goto drop;

  	}

  	seq = 0;

  	if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {

  		XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);

  		goto drop;

  	}

  	daddr = (xfrm_address_t *)(skb_network_header(skb) +
  				   XFRM_SPI_SKB_CB(skb)->daddroff);

  	do {

  		if (skb->sp->len == XFRM_MAX_DEPTH) {

  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);

  			goto drop;

  		}

  		x = xfrm_state_lookup(net, mark, daddr, spi, nexthdr, family);

  		if (x == NULL) {

  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);

  			xfrm_audit_state_notfound(skb, family, spi, seq);

  			goto drop;

  		}

  		skb->sp->xvec[skb->sp->len++] = x;

  lock:

  		spin_lock(&x->lock);

  		if (unlikely(x->km.state != XFRM_STATE_VALID)) {

  			if (x->km.state == XFRM_STATE_ACQ)
  				XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
  			else
  				XFRM_INC_STATS(net,
  					       LINUX_MIB_XFRMINSTATEINVALID);

  			goto drop_unlock;

  		}

  		if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
  			goto drop_unlock;
  		}

  		if (x->repl->check(x, skb, seq)) {

  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);

  			goto drop_unlock;

  		}

  		if (xfrm_state_check_expire(x)) {

  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);

  			goto drop_unlock;

  		}

  		spin_unlock(&x->lock);

  		if (xfrm_tunnel_check(skb, x, family)) {
  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
  			goto drop;
  		}

  		seq_hi = htonl(xfrm_replay_seqhi(x, seq));

  		XFRM_SKB_CB(skb)->seq.input.low = seq;

  		XFRM_SKB_CB(skb)->seq.input.hi = seq_hi;

  		skb_dst_force(skb);

  		dev_hold(skb->dev);

  		if (crypto_done)
  			nexthdr = x->type_offload->input_tail(x, skb);
  		else
  			nexthdr = x->type->input(x, skb);

  		if (nexthdr == -EINPROGRESS)
  			return 0;

  resume:

  		dev_put(skb->dev);

  		spin_lock(&x->lock);

  		if (nexthdr <= 0) {

  			if (nexthdr == -EBADMSG) {
  				xfrm_audit_state_icvfail(x, skb,
  							 x->type->proto);

  				x->stats.integrity_failed++;

  			}

  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);

  			goto drop_unlock;

  		}

  		/* only the first xfrm gets the encap type */
  		encap_type = 0;

  		if (async && x->repl->recheck(x, skb, seq)) {

  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
  			goto drop_unlock;
  		}

  		x->repl->advance(x, seq);

  
  		x->curlft.bytes += skb->len;
  		x->curlft.packets++;
  
  		spin_unlock(&x->lock);

  		XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;

  		inner_mode = x->inner_mode;
  
  		if (x->sel.family == AF_UNSPEC) {
  			inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);

  			if (inner_mode == NULL) {
  				XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);

  				goto drop;

  			}

  		}
  
  		if (inner_mode->input(x, skb)) {

  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);

  			goto drop;

  		}

  
  		if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
  			decaps = 1;
  			break;
  		}

  		/*
  		 * We need the inner address.  However, we only get here for
  		 * transport mode so the outer address is identical.
  		 */
  		daddr = &x->id.daddr;

  		family = x->outer_mode->afinfo->family;

  		err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);

  		if (err < 0) {

  			XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);

  			goto drop;

  		}

  	} while (!err);

  	err = xfrm_rcv_cb(skb, family, x->type->proto, 0);
  	if (err)
  		goto drop;

  	nf_reset(skb);
  
  	if (decaps) {

  		if (skb->sp)
  			skb->sp->olen = 0;

  		skb_dst_drop(skb);

  		gro_cells_receive(&gro_cells, skb);

  		return 0;
  	} else {

  		xo = xfrm_offload(skb);
  		if (xo)
  			xfrm_gro = xo->flags & XFRM_GRO;

  		err = x->inner_mode->afinfo->transport_finish(skb, xfrm_gro || async);

  		if (xfrm_gro) {

  			if (skb->sp)
  				skb->sp->olen = 0;

  			skb_dst_drop(skb);
  			gro_cells_receive(&gro_cells, skb);
  			return err;
  		}
  
  		return err;

  	}
  
  drop_unlock:
  	spin_unlock(&x->lock);

  drop:

  	xfrm_rcv_cb(skb, family, x && x->type ? x->type->proto : nexthdr, -1);

  	kfree_skb(skb);
  	return 0;
  }
  EXPORT_SYMBOL(xfrm_input);

  int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
  {
  	return xfrm_input(skb, nexthdr, 0, -1);
  }
  EXPORT_SYMBOL(xfrm_input_resume);

  static void xfrm_trans_reinject(unsigned long data)
  {
  	struct xfrm_trans_tasklet *trans = (void *)data;
  	struct sk_buff_head queue;
  	struct sk_buff *skb;
  
  	__skb_queue_head_init(&queue);
  	skb_queue_splice_init(&trans->queue, &queue);
  
  	while ((skb = __skb_dequeue(&queue)))
  		XFRM_TRANS_SKB_CB(skb)->finish(dev_net(skb->dev), NULL, skb);
  }
  
  int xfrm_trans_queue(struct sk_buff *skb,
  		     int (*finish)(struct net *, struct sock *,
  				   struct sk_buff *))
  {
  	struct xfrm_trans_tasklet *trans;
  
  	trans = this_cpu_ptr(&xfrm_trans_tasklet);
  
  	if (skb_queue_len(&trans->queue) >= netdev_max_backlog)
  		return -ENOBUFS;
  
  	XFRM_TRANS_SKB_CB(skb)->finish = finish;

  	__skb_queue_tail(&trans->queue, skb);

  	tasklet_schedule(&trans->tasklet);
  	return 0;
  }
  EXPORT_SYMBOL(xfrm_trans_queue);

  void __init xfrm_input_init(void)
  {

  	int err;

  	int i;

  
  	init_dummy_netdev(&xfrm_napi_dev);
  	err = gro_cells_init(&gro_cells, &xfrm_napi_dev);
  	if (err)
  		gro_cells.cells = NULL;

  	secpath_cachep = kmem_cache_create("secpath_cache",
  					   sizeof(struct sec_path),

  					   0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,

  					   NULL);

  
  	for_each_possible_cpu(i) {
  		struct xfrm_trans_tasklet *trans;
  
  		trans = &per_cpu(xfrm_trans_tasklet, i);
  		__skb_queue_head_init(&trans->queue);
  		tasklet_init(&trans->tasklet, xfrm_trans_reinject,
  			     (unsigned long)trans);
  	}

  }