/*
 * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
 * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *	- Redistributions of source code must retain the above
 *	  copyright notice, this list of conditions and the following
 *	  disclaimer.
 *
 *	- Redistributions in binary form must reproduce the above
 *	  copyright notice, this list of conditions and the following
 *	  disclaimer in the documentation and/or other materials
 *	  provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/if.h>
#include <linux/if_vlan.h>
#include <net/udp_tunnel.h>
#include <net/sch_generic.h>
#include <linux/netfilter.h>
#include <rdma/ib_addr.h>

#include "rxe.h"
#include "rxe_net.h"
#include "rxe_loc.h"

static LIST_HEAD(rxe_dev_list);
static spinlock_t dev_list_lock; /* spinlock for device list */

struct rxe_dev *net_to_rxe(struct net_device *ndev)
{
	struct rxe_dev *rxe;
	struct rxe_dev *found = NULL;

	spin_lock_bh(&dev_list_lock);
	list_for_each_entry(rxe, &rxe_dev_list, list) {
		if (rxe->ndev == ndev) {
			found = rxe;
			break;
		}
	}
	spin_unlock_bh(&dev_list_lock);

	return found;
}

struct rxe_dev *get_rxe_by_name(const char *name)
{
	struct rxe_dev *rxe;
	struct rxe_dev *found = NULL;

	spin_lock_bh(&dev_list_lock);
	list_for_each_entry(rxe, &rxe_dev_list, list) {
		if (!strcmp(name, rxe->ib_dev.name)) {
			found = rxe;
			break;
		}
	}
	spin_unlock_bh(&dev_list_lock);
	return found;
}


struct rxe_recv_sockets recv_sockets;

static __be64 rxe_mac_to_eui64(struct net_device *ndev)
{
	unsigned char *mac_addr = ndev->dev_addr;
	__be64 eui64;
	unsigned char *dst = (unsigned char *)&eui64;

	dst[0] = mac_addr[0] ^ 2;
	dst[1] = mac_addr[1];
	dst[2] = mac_addr[2];
	dst[3] = 0xff;
	dst[4] = 0xfe;
	dst[5] = mac_addr[3];
	dst[6] = mac_addr[4];
	dst[7] = mac_addr[5];

	return eui64;
}

static __be64 node_guid(struct rxe_dev *rxe)
{
	return rxe_mac_to_eui64(rxe->ndev);
}

static __be64 port_guid(struct rxe_dev *rxe)
{
	return rxe_mac_to_eui64(rxe->ndev);
}

static struct device *dma_device(struct rxe_dev *rxe)
{
	struct net_device *ndev;

	ndev = rxe->ndev;

	if (ndev->priv_flags & IFF_802_1Q_VLAN)
		ndev = vlan_dev_real_dev(ndev);

	return ndev->dev.parent;
}

static int mcast_add(struct rxe_dev *rxe, union ib_gid *mgid)
{
	int err;
	unsigned char ll_addr[ETH_ALEN];

	ipv6_eth_mc_map((struct in6_addr *)mgid->raw, ll_addr);
	err = dev_mc_add(rxe->ndev, ll_addr);

	return err;
}

static int mcast_delete(struct rxe_dev *rxe, union ib_gid *mgid)
{
	int err;
	unsigned char ll_addr[ETH_ALEN];

	ipv6_eth_mc_map((struct in6_addr *)mgid->raw, ll_addr);
	err = dev_mc_del(rxe->ndev, ll_addr);

	return err;
}

static struct dst_entry *rxe_find_route4(struct net_device *ndev,
				  struct in_addr *saddr,
				  struct in_addr *daddr)
{
	struct rtable *rt;
	struct flowi4 fl = { { 0 } };

	memset(&fl, 0, sizeof(fl));
	fl.flowi4_oif = ndev->ifindex;
	memcpy(&fl.saddr, saddr, sizeof(*saddr));
	memcpy(&fl.daddr, daddr, sizeof(*daddr));
	fl.flowi4_proto = IPPROTO_UDP;

	rt = ip_route_output_key(&init_net, &fl);
	if (IS_ERR(rt)) {
		pr_err_ratelimited("no route to %pI4\n", &daddr->s_addr);
		return NULL;
	}

	return &rt->dst;
}

#if IS_ENABLED(CONFIG_IPV6)
static struct dst_entry *rxe_find_route6(struct net_device *ndev,
					 struct in6_addr *saddr,
					 struct in6_addr *daddr)
{
	struct dst_entry *ndst;
	struct flowi6 fl6 = { { 0 } };

	memset(&fl6, 0, sizeof(fl6));
	fl6.flowi6_oif = ndev->ifindex;
	memcpy(&fl6.saddr, saddr, sizeof(*saddr));
	memcpy(&fl6.daddr, daddr, sizeof(*daddr));
	fl6.flowi6_proto = IPPROTO_UDP;

	if (unlikely(ipv6_stub->ipv6_dst_lookup(sock_net(recv_sockets.sk6->sk),
						recv_sockets.sk6->sk, &ndst, &fl6))) {
		pr_err_ratelimited("no route to %pI6\n", daddr);
		goto put;
	}

	if (unlikely(ndst->error)) {
		pr_err("no route to %pI6\n", daddr);
		goto put;
	}

	return ndst;
put:
	dst_release(ndst);
	return NULL;
}

#else

static struct dst_entry *rxe_find_route6(struct net_device *ndev,
					 struct in6_addr *saddr,
					 struct in6_addr *daddr)
{
	return NULL;
}

#endif

static int rxe_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
{
	struct udphdr *udph;
	struct net_device *ndev = skb->dev;
	struct rxe_dev *rxe = net_to_rxe(ndev);
	struct rxe_pkt_info *pkt = SKB_TO_PKT(skb);

	if (!rxe)
		goto drop;

	if (skb_linearize(skb)) {
		pr_err("skb_linearize failed\n");
		goto drop;
	}

	udph = udp_hdr(skb);
	pkt->rxe = rxe;
	pkt->port_num = 1;
	pkt->hdr = (u8 *)(udph + 1);
	pkt->mask = RXE_GRH_MASK;
	pkt->paylen = be16_to_cpu(udph->len) - sizeof(*udph);

	return rxe_rcv(skb);
drop:
	kfree_skb(skb);
	return 0;
}

static struct socket *rxe_setup_udp_tunnel(struct net *net, __be16 port,
					   bool ipv6)
{
	int err;
	struct socket *sock;
	struct udp_port_cfg udp_cfg = {0};
	struct udp_tunnel_sock_cfg tnl_cfg = {0};

	if (ipv6) {
		udp_cfg.family = AF_INET6;
		udp_cfg.ipv6_v6only = 1;
	} else {
		udp_cfg.family = AF_INET;
	}

	udp_cfg.local_udp_port = port;

	/* Create UDP socket */
	err = udp_sock_create(net, &udp_cfg, &sock);
	if (err < 0) {
		pr_err("failed to create udp socket. err = %d\n", err);
		return ERR_PTR(err);
	}

	tnl_cfg.encap_type = 1;
	tnl_cfg.encap_rcv = rxe_udp_encap_recv;

	/* Setup UDP tunnel */
	setup_udp_tunnel_sock(net, sock, &tnl_cfg);

	return sock;
}

void rxe_release_udp_tunnel(struct socket *sk)
{
	if (sk)
		udp_tunnel_sock_release(sk);
}

static void prepare_udp_hdr(struct sk_buff *skb, __be16 src_port,
			    __be16 dst_port)
{
	struct udphdr *udph;

	__skb_push(skb, sizeof(*udph));
	skb_reset_transport_header(skb);
	udph = udp_hdr(skb);

	udph->dest = dst_port;
	udph->source = src_port;
	udph->len = htons(skb->len);
	udph->check = 0;
}

static void prepare_ipv4_hdr(struct dst_entry *dst, struct sk_buff *skb,
			     __be32 saddr, __be32 daddr, __u8 proto,
			     __u8 tos, __u8 ttl, __be16 df, bool xnet)
{
	struct iphdr *iph;

	skb_scrub_packet(skb, xnet);

	skb_clear_hash(skb);
	skb_dst_set(skb, dst);
	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));

	skb_push(skb, sizeof(struct iphdr));
	skb_reset_network_header(skb);

	iph = ip_hdr(skb);

	iph->version	=	IPVERSION;
	iph->ihl	=	sizeof(struct iphdr) >> 2;
	iph->frag_off	=	df;
	iph->protocol	=	proto;
	iph->tos	=	tos;
	iph->daddr	=	daddr;
	iph->saddr	=	saddr;
	iph->ttl	=	ttl;
	__ip_select_ident(dev_net(dst->dev), iph,
			  skb_shinfo(skb)->gso_segs ?: 1);
	iph->tot_len = htons(skb->len);
	ip_send_check(iph);
}

static void prepare_ipv6_hdr(struct dst_entry *dst, struct sk_buff *skb,
			     struct in6_addr *saddr, struct in6_addr *daddr,
			     __u8 proto, __u8 prio, __u8 ttl)
{
	struct ipv6hdr *ip6h;

	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
	IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED
			    | IPSKB_REROUTED);
	skb_dst_set(skb, dst);

	__skb_push(skb, sizeof(*ip6h));
	skb_reset_network_header(skb);
	ip6h		  = ipv6_hdr(skb);
	ip6_flow_hdr(ip6h, prio, htonl(0));
	ip6h->payload_len = htons(skb->len);
	ip6h->nexthdr     = proto;
	ip6h->hop_limit   = ttl;
	ip6h->daddr	  = *daddr;
	ip6h->saddr	  = *saddr;
	ip6h->payload_len = htons(skb->len - sizeof(*ip6h));
}

static int prepare4(struct rxe_dev *rxe, struct rxe_pkt_info *pkt,
		    struct sk_buff *skb, struct rxe_av *av)
{
	struct dst_entry *dst;
	bool xnet = false;
	__be16 df = htons(IP_DF);
	struct in_addr *saddr = &av->sgid_addr._sockaddr_in.sin_addr;
	struct in_addr *daddr = &av->dgid_addr._sockaddr_in.sin_addr;

	dst = rxe_find_route4(rxe->ndev, saddr, daddr);
	if (!dst) {
		pr_err("Host not reachable\n");
		return -EHOSTUNREACH;
	}

	if (!memcmp(saddr, daddr, sizeof(*daddr)))
		pkt->mask |= RXE_LOOPBACK_MASK;

	prepare_udp_hdr(skb, htons(RXE_ROCE_V2_SPORT),
			htons(ROCE_V2_UDP_DPORT));

	prepare_ipv4_hdr(dst, skb, saddr->s_addr, daddr->s_addr, IPPROTO_UDP,
			 av->grh.traffic_class, av->grh.hop_limit, df, xnet);
	return 0;
}

static int prepare6(struct rxe_dev *rxe, struct rxe_pkt_info *pkt,
		    struct sk_buff *skb, struct rxe_av *av)
{
	struct dst_entry *dst;
	struct in6_addr *saddr = &av->sgid_addr._sockaddr_in6.sin6_addr;
	struct in6_addr *daddr = &av->dgid_addr._sockaddr_in6.sin6_addr;

	dst = rxe_find_route6(rxe->ndev, saddr, daddr);
	if (!dst) {
		pr_err("Host not reachable\n");
		return -EHOSTUNREACH;
	}

	if (!memcmp(saddr, daddr, sizeof(*daddr)))
		pkt->mask |= RXE_LOOPBACK_MASK;

	prepare_udp_hdr(skb, htons(RXE_ROCE_V2_SPORT),
			htons(ROCE_V2_UDP_DPORT));

	prepare_ipv6_hdr(dst, skb, saddr, daddr, IPPROTO_UDP,
			 av->grh.traffic_class,
			 av->grh.hop_limit);
	return 0;
}

static int prepare(struct rxe_dev *rxe, struct rxe_pkt_info *pkt,
		   struct sk_buff *skb, u32 *crc)
{
	int err = 0;
	struct rxe_av *av = rxe_get_av(pkt);

	if (av->network_type == RDMA_NETWORK_IPV4)
		err = prepare4(rxe, pkt, skb, av);
	else if (av->network_type == RDMA_NETWORK_IPV6)
		err = prepare6(rxe, pkt, skb, av);

	*crc = rxe_icrc_hdr(pkt, skb);

	return err;
}

static void rxe_skb_tx_dtor(struct sk_buff *skb)
{
	struct sock *sk = skb->sk;
	struct rxe_qp *qp = sk->sk_user_data;
	int skb_out = atomic_dec_return(&qp->skb_out);

	if (unlikely(qp->need_req_skb &&
		     skb_out < RXE_INFLIGHT_SKBS_PER_QP_LOW))
		rxe_run_task(&qp->req.task, 1);
}

static int send(struct rxe_dev *rxe, struct rxe_pkt_info *pkt,
		struct sk_buff *skb)
{
	struct sk_buff *nskb;
	struct rxe_av *av;
	int err;

	av = rxe_get_av(pkt);

	nskb = skb_clone(skb, GFP_ATOMIC);
	if (!nskb)
		return -ENOMEM;

	nskb->destructor = rxe_skb_tx_dtor;
	nskb->sk = pkt->qp->sk->sk;

	if (av->network_type == RDMA_NETWORK_IPV4) {
		err = ip_local_out(dev_net(skb_dst(skb)->dev), nskb->sk, nskb);
	} else if (av->network_type == RDMA_NETWORK_IPV6) {
		err = ip6_local_out(dev_net(skb_dst(skb)->dev), nskb->sk, nskb);
	} else {
		pr_err("Unknown layer 3 protocol: %d\n", av->network_type);
		kfree_skb(nskb);
		return -EINVAL;
	}

	if (unlikely(net_xmit_eval(err))) {
		pr_debug("error sending packet: %d\n", err);
		return -EAGAIN;
	}

	kfree_skb(skb);

	return 0;
}

static int loopback(struct sk_buff *skb)
{
	return rxe_rcv(skb);
}

static inline int addr_same(struct rxe_dev *rxe, struct rxe_av *av)
{
	return rxe->port.port_guid == av->grh.dgid.global.interface_id;
}

static struct sk_buff *init_packet(struct rxe_dev *rxe, struct rxe_av *av,
				   int paylen, struct rxe_pkt_info *pkt)
{
	unsigned int hdr_len;
	struct sk_buff *skb;

	if (av->network_type == RDMA_NETWORK_IPV4)
		hdr_len = ETH_HLEN + sizeof(struct udphdr) +
			sizeof(struct iphdr);
	else
		hdr_len = ETH_HLEN + sizeof(struct udphdr) +
			sizeof(struct ipv6hdr);

	skb = alloc_skb(paylen + hdr_len + LL_RESERVED_SPACE(rxe->ndev),
			GFP_ATOMIC);
	if (unlikely(!skb))
		return NULL;

	skb_reserve(skb, hdr_len + LL_RESERVED_SPACE(rxe->ndev));

	skb->dev	= rxe->ndev;
	if (av->network_type == RDMA_NETWORK_IPV4)
		skb->protocol = htons(ETH_P_IP);
	else
		skb->protocol = htons(ETH_P_IPV6);

	pkt->rxe	= rxe;
	pkt->port_num	= 1;
	pkt->hdr	= skb_put(skb, paylen);
	pkt->mask	|= RXE_GRH_MASK;

	memset(pkt->hdr, 0, paylen);

	return skb;
}

/*
 * this is required by rxe_cfg to match rxe devices in
 * /sys/class/infiniband up with their underlying ethernet devices
 */
static char *parent_name(struct rxe_dev *rxe, unsigned int port_num)
{
	return rxe->ndev->name;
}

static enum rdma_link_layer link_layer(struct rxe_dev *rxe,
				       unsigned int port_num)
{
	return IB_LINK_LAYER_ETHERNET;
}

static struct rxe_ifc_ops ifc_ops = {
	.node_guid	= node_guid,
	.port_guid	= port_guid,
	.dma_device	= dma_device,
	.mcast_add	= mcast_add,
	.mcast_delete	= mcast_delete,
	.prepare	= prepare,
	.send		= send,
	.loopback	= loopback,
	.init_packet	= init_packet,
	.parent_name	= parent_name,
	.link_layer	= link_layer,
};

struct rxe_dev *rxe_net_add(struct net_device *ndev)
{
	int err;
	struct rxe_dev *rxe = NULL;

	rxe = (struct rxe_dev *)ib_alloc_device(sizeof(*rxe));
	if (!rxe)
		return NULL;

	rxe->ifc_ops = &ifc_ops;
	rxe->ndev = ndev;

	err = rxe_add(rxe, ndev->mtu);
	if (err) {
		ib_dealloc_device(&rxe->ib_dev);
		return NULL;
	}

	spin_lock_bh(&dev_list_lock);
	list_add_tail(&rxe->list, &rxe_dev_list);
	spin_unlock_bh(&dev_list_lock);
	return rxe;
}

void rxe_remove_all(void)
{
	spin_lock_bh(&dev_list_lock);
	while (!list_empty(&rxe_dev_list)) {
		struct rxe_dev *rxe =
			list_first_entry(&rxe_dev_list, struct rxe_dev, list);

		list_del(&rxe->list);
		spin_unlock_bh(&dev_list_lock);
		rxe_remove(rxe);
		spin_lock_bh(&dev_list_lock);
	}
	spin_unlock_bh(&dev_list_lock);
}
EXPORT_SYMBOL(rxe_remove_all);

static void rxe_port_event(struct rxe_dev *rxe,
			   enum ib_event_type event)
{
	struct ib_event ev;

	ev.device = &rxe->ib_dev;
	ev.element.port_num = 1;
	ev.event = event;

	ib_dispatch_event(&ev);
}

/* Caller must hold net_info_lock */
void rxe_port_up(struct rxe_dev *rxe)
{
	struct rxe_port *port;

	port = &rxe->port;
	port->attr.state = IB_PORT_ACTIVE;
	port->attr.phys_state = IB_PHYS_STATE_LINK_UP;

	rxe_port_event(rxe, IB_EVENT_PORT_ACTIVE);
	pr_info("set %s active\n", rxe->ib_dev.name);
}

/* Caller must hold net_info_lock */
void rxe_port_down(struct rxe_dev *rxe)
{
	struct rxe_port *port;

	port = &rxe->port;
	port->attr.state = IB_PORT_DOWN;
	port->attr.phys_state = IB_PHYS_STATE_LINK_DOWN;

	rxe_port_event(rxe, IB_EVENT_PORT_ERR);
	pr_info("set %s down\n", rxe->ib_dev.name);
}

static int rxe_notify(struct notifier_block *not_blk,
		      unsigned long event,
		      void *arg)
{
	struct net_device *ndev = netdev_notifier_info_to_dev(arg);
	struct rxe_dev *rxe = net_to_rxe(ndev);

	if (!rxe)
		goto out;

	switch (event) {
	case NETDEV_UNREGISTER:
		list_del(&rxe->list);
		rxe_remove(rxe);
		break;
	case NETDEV_UP:
		rxe_port_up(rxe);
		break;
	case NETDEV_DOWN:
		rxe_port_down(rxe);
		break;
	case NETDEV_CHANGEMTU:
		pr_info("%s changed mtu to %d\n", ndev->name, ndev->mtu);
		rxe_set_mtu(rxe, ndev->mtu);
		break;
	case NETDEV_REBOOT:
	case NETDEV_CHANGE:
	case NETDEV_GOING_DOWN:
	case NETDEV_CHANGEADDR:
	case NETDEV_CHANGENAME:
	case NETDEV_FEAT_CHANGE:
	default:
		pr_info("ignoring netdev event = %ld for %s\n",
			event, ndev->name);
		break;
	}
out:
	return NOTIFY_OK;
}

struct notifier_block rxe_net_notifier = {
	.notifier_call = rxe_notify,
};

int rxe_net_ipv4_init(void)
{
	spin_lock_init(&dev_list_lock);

	recv_sockets.sk4 = rxe_setup_udp_tunnel(&init_net,
				htons(ROCE_V2_UDP_DPORT), false);
	if (IS_ERR(recv_sockets.sk4)) {
		recv_sockets.sk4 = NULL;
		pr_err("Failed to create IPv4 UDP tunnel\n");
		return -1;
	}

	return 0;
}

int rxe_net_ipv6_init(void)
{
#if IS_ENABLED(CONFIG_IPV6)

	spin_lock_init(&dev_list_lock);

	recv_sockets.sk6 = rxe_setup_udp_tunnel(&init_net,
						htons(ROCE_V2_UDP_DPORT), true);
	if (IS_ERR(recv_sockets.sk6)) {
		recv_sockets.sk6 = NULL;
		pr_err("Failed to create IPv6 UDP tunnel\n");
		return -1;
	}
#endif
	return 0;
}

void rxe_net_exit(void)
{
	rxe_release_udp_tunnel(recv_sockets.sk6);
	rxe_release_udp_tunnel(recv_sockets.sk4);
	unregister_netdevice_notifier(&rxe_net_notifier);
}

int rxe_net_init(void)
{
	int err;

	recv_sockets.sk6 = NULL;

	err = rxe_net_ipv4_init();
	if (err)
		return err;
	err = rxe_net_ipv6_init();
	if (err)
		goto err_out;
	err = register_netdevice_notifier(&rxe_net_notifier);
	if (err) {
		pr_err("Failed to register netdev notifier\n");
		goto err_out;
	}
	return 0;
err_out:
	rxe_net_exit();
	return err;
}