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amt.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/* Copyright (c) 2021 Taehee Yoo <[email protected]> */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/udp.h>
#include <linux/jhash.h>
#include <linux/if_tunnel.h>
#include <linux/net.h>
#include <linux/igmp.h>
#include <linux/workqueue.h>
#include <net/pkt_sched.h>
#include <net/net_namespace.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/udp_tunnel.h>
#include <net/icmp.h>
#include <net/mld.h>
#include <net/amt.h>
#include <uapi/linux/amt.h>
#include <linux/security.h>
#include <net/gro_cells.h>
#include <net/ipv6.h>
#include <net/if_inet6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/inet_common.h>
#include <net/ip6_checksum.h>
static struct workqueue_struct *amt_wq;
static HLIST_HEAD(source_gc_list);
/* Lock for source_gc_list */
static spinlock_t source_gc_lock;
static struct delayed_work source_gc_wq;
static char *status_str[] = {
"AMT_STATUS_INIT",
"AMT_STATUS_SENT_DISCOVERY",
"AMT_STATUS_RECEIVED_DISCOVERY",
"AMT_STATUS_SENT_ADVERTISEMENT",
"AMT_STATUS_RECEIVED_ADVERTISEMENT",
"AMT_STATUS_SENT_REQUEST",
"AMT_STATUS_RECEIVED_REQUEST",
"AMT_STATUS_SENT_QUERY",
"AMT_STATUS_RECEIVED_QUERY",
"AMT_STATUS_SENT_UPDATE",
"AMT_STATUS_RECEIVED_UPDATE",
};
static char *type_str[] = {
"", /* Type 0 is not defined */
"AMT_MSG_DISCOVERY",
"AMT_MSG_ADVERTISEMENT",
"AMT_MSG_REQUEST",
"AMT_MSG_MEMBERSHIP_QUERY",
"AMT_MSG_MEMBERSHIP_UPDATE",
"AMT_MSG_MULTICAST_DATA",
"AMT_MSG_TEARDOWN",
};
static char *action_str[] = {
"AMT_ACT_GMI",
"AMT_ACT_GMI_ZERO",
"AMT_ACT_GT",
"AMT_ACT_STATUS_FWD_NEW",
"AMT_ACT_STATUS_D_FWD_NEW",
"AMT_ACT_STATUS_NONE_NEW",
};
static struct igmpv3_grec igmpv3_zero_grec;
#if IS_ENABLED(CONFIG_IPV6)
#define MLD2_ALL_NODE_INIT { { { 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 } } }
static struct in6_addr mld2_all_node = MLD2_ALL_NODE_INIT;
static struct mld2_grec mldv2_zero_grec;
#endif
static struct amt_skb_cb *amt_skb_cb(struct sk_buff *skb)
{
BUILD_BUG_ON(sizeof(struct amt_skb_cb) + sizeof(struct tc_skb_cb) >
sizeof_field(struct sk_buff, cb));
return (struct amt_skb_cb *)((void *)skb->cb +
sizeof(struct tc_skb_cb));
}
static void __amt_source_gc_work(void)
{
struct amt_source_node *snode;
struct hlist_head gc_list;
struct hlist_node *t;
spin_lock_bh(&source_gc_lock);
hlist_move_list(&source_gc_list, &gc_list);
spin_unlock_bh(&source_gc_lock);
hlist_for_each_entry_safe(snode, t, &gc_list, node) {
hlist_del_rcu(&snode->node);
kfree_rcu(snode, rcu);
}
}
static void amt_source_gc_work(struct work_struct *work)
{
__amt_source_gc_work();
spin_lock_bh(&source_gc_lock);
mod_delayed_work(amt_wq, &source_gc_wq,
msecs_to_jiffies(AMT_GC_INTERVAL));
spin_unlock_bh(&source_gc_lock);
}
static bool amt_addr_equal(union amt_addr *a, union amt_addr *b)
{
return !memcmp(a, b, sizeof(union amt_addr));
}
static u32 amt_source_hash(struct amt_tunnel_list *tunnel, union amt_addr *src)
{
u32 hash = jhash(src, sizeof(*src), tunnel->amt->hash_seed);
return reciprocal_scale(hash, tunnel->amt->hash_buckets);
}
static bool amt_status_filter(struct amt_source_node *snode,
enum amt_filter filter)
{
bool rc = false;
switch (filter) {
case AMT_FILTER_FWD:
if (snode->status == AMT_SOURCE_STATUS_FWD &&
snode->flags == AMT_SOURCE_OLD)
rc = true;
break;
case AMT_FILTER_D_FWD:
if (snode->status == AMT_SOURCE_STATUS_D_FWD &&
snode->flags == AMT_SOURCE_OLD)
rc = true;
break;
case AMT_FILTER_FWD_NEW:
if (snode->status == AMT_SOURCE_STATUS_FWD &&
snode->flags == AMT_SOURCE_NEW)
rc = true;
break;
case AMT_FILTER_D_FWD_NEW:
if (snode->status == AMT_SOURCE_STATUS_D_FWD &&
snode->flags == AMT_SOURCE_NEW)
rc = true;
break;
case AMT_FILTER_ALL:
rc = true;
break;
case AMT_FILTER_NONE_NEW:
if (snode->status == AMT_SOURCE_STATUS_NONE &&
snode->flags == AMT_SOURCE_NEW)
rc = true;
break;
case AMT_FILTER_BOTH:
if ((snode->status == AMT_SOURCE_STATUS_D_FWD ||
snode->status == AMT_SOURCE_STATUS_FWD) &&
snode->flags == AMT_SOURCE_OLD)
rc = true;
break;
case AMT_FILTER_BOTH_NEW:
if ((snode->status == AMT_SOURCE_STATUS_D_FWD ||
snode->status == AMT_SOURCE_STATUS_FWD) &&
snode->flags == AMT_SOURCE_NEW)
rc = true;
break;
default:
WARN_ON_ONCE(1);
break;
}
return rc;
}
static struct amt_source_node *amt_lookup_src(struct amt_tunnel_list *tunnel,
struct amt_group_node *gnode,
enum amt_filter filter,
union amt_addr *src)
{
u32 hash = amt_source_hash(tunnel, src);
struct amt_source_node *snode;
hlist_for_each_entry_rcu(snode, &gnode->sources[hash], node)
if (amt_status_filter(snode, filter) &&
amt_addr_equal(&snode->source_addr, src))
return snode;
return NULL;
}
static u32 amt_group_hash(struct amt_tunnel_list *tunnel, union amt_addr *group)
{
u32 hash = jhash(group, sizeof(*group), tunnel->amt->hash_seed);
return reciprocal_scale(hash, tunnel->amt->hash_buckets);
}
static struct amt_group_node *amt_lookup_group(struct amt_tunnel_list *tunnel,
union amt_addr *group,
union amt_addr *host,
bool v6)
{
u32 hash = amt_group_hash(tunnel, group);
struct amt_group_node *gnode;
hlist_for_each_entry_rcu(gnode, &tunnel->groups[hash], node) {
if (amt_addr_equal(&gnode->group_addr, group) &&
amt_addr_equal(&gnode->host_addr, host) &&
gnode->v6 == v6)
return gnode;
}
return NULL;
}
static void amt_destroy_source(struct amt_source_node *snode)
{
struct amt_group_node *gnode = snode->gnode;
struct amt_tunnel_list *tunnel;
tunnel = gnode->tunnel_list;
if (!gnode->v6) {
netdev_dbg(snode->gnode->amt->dev,
"Delete source %pI4 from %pI4\n",
&snode->source_addr.ip4,
&gnode->group_addr.ip4);
#if IS_ENABLED(CONFIG_IPV6)
} else {
netdev_dbg(snode->gnode->amt->dev,
"Delete source %pI6 from %pI6\n",
&snode->source_addr.ip6,
&gnode->group_addr.ip6);
#endif
}
cancel_delayed_work(&snode->source_timer);
hlist_del_init_rcu(&snode->node);
tunnel->nr_sources--;
gnode->nr_sources--;
spin_lock_bh(&source_gc_lock);
hlist_add_head_rcu(&snode->node, &source_gc_list);
spin_unlock_bh(&source_gc_lock);
}
static void amt_del_group(struct amt_dev *amt, struct amt_group_node *gnode)
{
struct amt_source_node *snode;
struct hlist_node *t;
int i;
if (cancel_delayed_work(&gnode->group_timer))
dev_put(amt->dev);
hlist_del_rcu(&gnode->node);
gnode->tunnel_list->nr_groups--;
if (!gnode->v6)
netdev_dbg(amt->dev, "Leave group %pI4\n",
&gnode->group_addr.ip4);
#if IS_ENABLED(CONFIG_IPV6)
else
netdev_dbg(amt->dev, "Leave group %pI6\n",
&gnode->group_addr.ip6);
#endif
for (i = 0; i < amt->hash_buckets; i++)
hlist_for_each_entry_safe(snode, t, &gnode->sources[i], node)
amt_destroy_source(snode);
/* tunnel->lock was acquired outside of amt_del_group()
* But rcu_read_lock() was acquired too so It's safe.
*/
kfree_rcu(gnode, rcu);
}
/* If a source timer expires with a router filter-mode for the group of
* INCLUDE, the router concludes that traffic from this particular
* source is no longer desired on the attached network, and deletes the
* associated source record.
*/
static void amt_source_work(struct work_struct *work)
{
struct amt_source_node *snode = container_of(to_delayed_work(work),
struct amt_source_node,
source_timer);
struct amt_group_node *gnode = snode->gnode;
struct amt_dev *amt = gnode->amt;
struct amt_tunnel_list *tunnel;
tunnel = gnode->tunnel_list;
spin_lock_bh(&tunnel->lock);
rcu_read_lock();
if (gnode->filter_mode == MCAST_INCLUDE) {
amt_destroy_source(snode);
if (!gnode->nr_sources)
amt_del_group(amt, gnode);
} else {
/* When a router filter-mode for a group is EXCLUDE,
* source records are only deleted when the group timer expires
*/
snode->status = AMT_SOURCE_STATUS_D_FWD;
}
rcu_read_unlock();
spin_unlock_bh(&tunnel->lock);
}
static void amt_act_src(struct amt_tunnel_list *tunnel,
struct amt_group_node *gnode,
struct amt_source_node *snode,
enum amt_act act)
{
struct amt_dev *amt = tunnel->amt;
switch (act) {
case AMT_ACT_GMI:
mod_delayed_work(amt_wq, &snode->source_timer,
msecs_to_jiffies(amt_gmi(amt)));
break;
case AMT_ACT_GMI_ZERO:
cancel_delayed_work(&snode->source_timer);
break;
case AMT_ACT_GT:
mod_delayed_work(amt_wq, &snode->source_timer,
gnode->group_timer.timer.expires);
break;
case AMT_ACT_STATUS_FWD_NEW:
snode->status = AMT_SOURCE_STATUS_FWD;
snode->flags = AMT_SOURCE_NEW;
break;
case AMT_ACT_STATUS_D_FWD_NEW:
snode->status = AMT_SOURCE_STATUS_D_FWD;
snode->flags = AMT_SOURCE_NEW;
break;
case AMT_ACT_STATUS_NONE_NEW:
cancel_delayed_work(&snode->source_timer);
snode->status = AMT_SOURCE_STATUS_NONE;
snode->flags = AMT_SOURCE_NEW;
break;
default:
WARN_ON_ONCE(1);
return;
}
if (!gnode->v6)
netdev_dbg(amt->dev, "Source %pI4 from %pI4 Acted %s\n",
&snode->source_addr.ip4,
&gnode->group_addr.ip4,
action_str[act]);
#if IS_ENABLED(CONFIG_IPV6)
else
netdev_dbg(amt->dev, "Source %pI6 from %pI6 Acted %s\n",
&snode->source_addr.ip6,
&gnode->group_addr.ip6,
action_str[act]);
#endif
}
static struct amt_source_node *amt_alloc_snode(struct amt_group_node *gnode,
union amt_addr *src)
{
struct amt_source_node *snode;
snode = kzalloc(sizeof(*snode), GFP_ATOMIC);
if (!snode)
return NULL;
memcpy(&snode->source_addr, src, sizeof(union amt_addr));
snode->gnode = gnode;
snode->status = AMT_SOURCE_STATUS_NONE;
snode->flags = AMT_SOURCE_NEW;
INIT_HLIST_NODE(&snode->node);
INIT_DELAYED_WORK(&snode->source_timer, amt_source_work);
return snode;
}
/* RFC 3810 - 7.2.2. Definition of Filter Timers
*
* Router Mode Filter Timer Actions/Comments
* ----------- ----------------- ----------------
*
* INCLUDE Not Used All listeners in
* INCLUDE mode.
*
* EXCLUDE Timer > 0 At least one listener
* in EXCLUDE mode.
*
* EXCLUDE Timer == 0 No more listeners in
* EXCLUDE mode for the
* multicast address.
* If the Requested List
* is empty, delete
* Multicast Address
* Record. If not, switch
* to INCLUDE filter mode;
* the sources in the
* Requested List are
* moved to the Include
* List, and the Exclude
* List is deleted.
*/
static void amt_group_work(struct work_struct *work)
{
struct amt_group_node *gnode = container_of(to_delayed_work(work),
struct amt_group_node,
group_timer);
struct amt_tunnel_list *tunnel = gnode->tunnel_list;
struct amt_dev *amt = gnode->amt;
struct amt_source_node *snode;
bool delete_group = true;
struct hlist_node *t;
int i, buckets;
buckets = amt->hash_buckets;
spin_lock_bh(&tunnel->lock);
if (gnode->filter_mode == MCAST_INCLUDE) {
/* Not Used */
spin_unlock_bh(&tunnel->lock);
goto out;
}
rcu_read_lock();
for (i = 0; i < buckets; i++) {
hlist_for_each_entry_safe(snode, t,
&gnode->sources[i], node) {
if (!delayed_work_pending(&snode->source_timer) ||
snode->status == AMT_SOURCE_STATUS_D_FWD) {
amt_destroy_source(snode);
} else {
delete_group = false;
snode->status = AMT_SOURCE_STATUS_FWD;
}
}
}
if (delete_group)
amt_del_group(amt, gnode);
else
gnode->filter_mode = MCAST_INCLUDE;
rcu_read_unlock();
spin_unlock_bh(&tunnel->lock);
out:
dev_put(amt->dev);
}
/* Non-existent group is created as INCLUDE {empty}:
*
* RFC 3376 - 5.1. Action on Change of Interface State
*
* If no interface state existed for that multicast address before
* the change (i.e., the change consisted of creating a new
* per-interface record), or if no state exists after the change
* (i.e., the change consisted of deleting a per-interface record),
* then the "non-existent" state is considered to have a filter mode
* of INCLUDE and an empty source list.
*/
static struct amt_group_node *amt_add_group(struct amt_dev *amt,
struct amt_tunnel_list *tunnel,
union amt_addr *group,
union amt_addr *host,
bool v6)
{
struct amt_group_node *gnode;
u32 hash;
int i;
if (tunnel->nr_groups >= amt->max_groups)
return ERR_PTR(-ENOSPC);
gnode = kzalloc(sizeof(*gnode) +
(sizeof(struct hlist_head) * amt->hash_buckets),
GFP_ATOMIC);
if (unlikely(!gnode))
return ERR_PTR(-ENOMEM);
gnode->amt = amt;
gnode->group_addr = *group;
gnode->host_addr = *host;
gnode->v6 = v6;
gnode->tunnel_list = tunnel;
gnode->filter_mode = MCAST_INCLUDE;
INIT_HLIST_NODE(&gnode->node);
INIT_DELAYED_WORK(&gnode->group_timer, amt_group_work);
for (i = 0; i < amt->hash_buckets; i++)
INIT_HLIST_HEAD(&gnode->sources[i]);
hash = amt_group_hash(tunnel, group);
hlist_add_head_rcu(&gnode->node, &tunnel->groups[hash]);
tunnel->nr_groups++;
if (!gnode->v6)
netdev_dbg(amt->dev, "Join group %pI4\n",
&gnode->group_addr.ip4);
#if IS_ENABLED(CONFIG_IPV6)
else
netdev_dbg(amt->dev, "Join group %pI6\n",
&gnode->group_addr.ip6);
#endif
return gnode;
}
static struct sk_buff *amt_build_igmp_gq(struct amt_dev *amt)
{
u8 ra[AMT_IPHDR_OPTS] = { IPOPT_RA, 4, 0, 0 };
int hlen = LL_RESERVED_SPACE(amt->dev);
int tlen = amt->dev->needed_tailroom;
struct igmpv3_query *ihv3;
void *csum_start = NULL;
__sum16 *csum = NULL;
struct sk_buff *skb;
struct ethhdr *eth;
struct iphdr *iph;
unsigned int len;
int offset;
len = hlen + tlen + sizeof(*iph) + AMT_IPHDR_OPTS + sizeof(*ihv3);
skb = netdev_alloc_skb_ip_align(amt->dev, len);
if (!skb)
return NULL;
skb_reserve(skb, hlen);
skb_push(skb, sizeof(*eth));
skb->protocol = htons(ETH_P_IP);
skb_reset_mac_header(skb);
skb->priority = TC_PRIO_CONTROL;
skb_put(skb, sizeof(*iph));
skb_put_data(skb, ra, sizeof(ra));
skb_put(skb, sizeof(*ihv3));
skb_pull(skb, sizeof(*eth));
skb_reset_network_header(skb);
iph = ip_hdr(skb);
iph->version = 4;
iph->ihl = (sizeof(struct iphdr) + AMT_IPHDR_OPTS) >> 2;
iph->tos = AMT_TOS;
iph->tot_len = htons(sizeof(*iph) + AMT_IPHDR_OPTS + sizeof(*ihv3));
iph->frag_off = htons(IP_DF);
iph->ttl = 1;
iph->id = 0;
iph->protocol = IPPROTO_IGMP;
iph->daddr = htonl(INADDR_ALLHOSTS_GROUP);
iph->saddr = htonl(INADDR_ANY);
ip_send_check(iph);
eth = eth_hdr(skb);
ether_addr_copy(eth->h_source, amt->dev->dev_addr);
ip_eth_mc_map(htonl(INADDR_ALLHOSTS_GROUP), eth->h_dest);
eth->h_proto = htons(ETH_P_IP);
ihv3 = skb_pull(skb, sizeof(*iph) + AMT_IPHDR_OPTS);
skb_reset_transport_header(skb);
ihv3->type = IGMP_HOST_MEMBERSHIP_QUERY;
ihv3->code = 1;
ihv3->group = 0;
ihv3->qqic = amt->qi;
ihv3->nsrcs = 0;
ihv3->resv = 0;
ihv3->suppress = false;
ihv3->qrv = READ_ONCE(amt->net->ipv4.sysctl_igmp_qrv);
ihv3->csum = 0;
csum = &ihv3->csum;
csum_start = (void *)ihv3;
*csum = ip_compute_csum(csum_start, sizeof(*ihv3));
offset = skb_transport_offset(skb);
skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
skb->ip_summed = CHECKSUM_NONE;
skb_push(skb, sizeof(*eth) + sizeof(*iph) + AMT_IPHDR_OPTS);
return skb;
}
static void amt_update_gw_status(struct amt_dev *amt, enum amt_status status,
bool validate)
{
if (validate && amt->status >= status)
return;
netdev_dbg(amt->dev, "Update GW status %s -> %s",
status_str[amt->status], status_str[status]);
WRITE_ONCE(amt->status, status);
}
static void __amt_update_relay_status(struct amt_tunnel_list *tunnel,
enum amt_status status,
bool validate)
{
if (validate && tunnel->status >= status)
return;
netdev_dbg(tunnel->amt->dev,
"Update Tunnel(IP = %pI4, PORT = %u) status %s -> %s",
&tunnel->ip4, ntohs(tunnel->source_port),
status_str[tunnel->status], status_str[status]);
tunnel->status = status;
}
static void amt_update_relay_status(struct amt_tunnel_list *tunnel,
enum amt_status status, bool validate)
{
spin_lock_bh(&tunnel->lock);
__amt_update_relay_status(tunnel, status, validate);
spin_unlock_bh(&tunnel->lock);
}
static void amt_send_discovery(struct amt_dev *amt)
{
struct amt_header_discovery *amtd;
int hlen, tlen, offset;
struct socket *sock;
struct udphdr *udph;
struct sk_buff *skb;
struct iphdr *iph;
struct rtable *rt;
struct flowi4 fl4;
u32 len;
int err;
rcu_read_lock();
sock = rcu_dereference(amt->sock);
if (!sock)
goto out;
if (!netif_running(amt->stream_dev) || !netif_running(amt->dev))
goto out;
rt = ip_route_output_ports(amt->net, &fl4, sock->sk,
amt->discovery_ip, amt->local_ip,
amt->gw_port, amt->relay_port,
IPPROTO_UDP, 0,
amt->stream_dev->ifindex);
if (IS_ERR(rt)) {
amt->dev->stats.tx_errors++;
goto out;
}
hlen = LL_RESERVED_SPACE(amt->dev);
tlen = amt->dev->needed_tailroom;
len = hlen + tlen + sizeof(*iph) + sizeof(*udph) + sizeof(*amtd);
skb = netdev_alloc_skb_ip_align(amt->dev, len);
if (!skb) {
ip_rt_put(rt);
amt->dev->stats.tx_errors++;
goto out;
}
skb->priority = TC_PRIO_CONTROL;
skb_dst_set(skb, &rt->dst);
len = sizeof(*iph) + sizeof(*udph) + sizeof(*amtd);
skb_reset_network_header(skb);
skb_put(skb, len);
amtd = skb_pull(skb, sizeof(*iph) + sizeof(*udph));
amtd->version = 0;
amtd->type = AMT_MSG_DISCOVERY;
amtd->reserved = 0;
amtd->nonce = amt->nonce;
skb_push(skb, sizeof(*udph));
skb_reset_transport_header(skb);
udph = udp_hdr(skb);
udph->source = amt->gw_port;
udph->dest = amt->relay_port;
udph->len = htons(sizeof(*udph) + sizeof(*amtd));
udph->check = 0;
offset = skb_transport_offset(skb);
skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
udph->check = csum_tcpudp_magic(amt->local_ip, amt->discovery_ip,
sizeof(*udph) + sizeof(*amtd),
IPPROTO_UDP, skb->csum);
skb_push(skb, sizeof(*iph));
iph = ip_hdr(skb);
iph->version = 4;
iph->ihl = (sizeof(struct iphdr)) >> 2;
iph->tos = AMT_TOS;
iph->frag_off = 0;
iph->ttl = ip4_dst_hoplimit(&rt->dst);
iph->daddr = amt->discovery_ip;
iph->saddr = amt->local_ip;
iph->protocol = IPPROTO_UDP;
iph->tot_len = htons(len);
skb->ip_summed = CHECKSUM_NONE;
ip_select_ident(amt->net, skb, NULL);
ip_send_check(iph);
err = ip_local_out(amt->net, sock->sk, skb);
if (unlikely(net_xmit_eval(err)))
amt->dev->stats.tx_errors++;
amt_update_gw_status(amt, AMT_STATUS_SENT_DISCOVERY, true);
out:
rcu_read_unlock();
}
static void amt_send_request(struct amt_dev *amt, bool v6)
{
struct amt_header_request *amtrh;
int hlen, tlen, offset;
struct socket *sock;
struct udphdr *udph;
struct sk_buff *skb;
struct iphdr *iph;
struct rtable *rt;
struct flowi4 fl4;
u32 len;
int err;
rcu_read_lock();
sock = rcu_dereference(amt->sock);
if (!sock)
goto out;
if (!netif_running(amt->stream_dev) || !netif_running(amt->dev))
goto out;
rt = ip_route_output_ports(amt->net, &fl4, sock->sk,
amt->remote_ip, amt->local_ip,
amt->gw_port, amt->relay_port,
IPPROTO_UDP, 0,
amt->stream_dev->ifindex);
if (IS_ERR(rt)) {
amt->dev->stats.tx_errors++;
goto out;
}
hlen = LL_RESERVED_SPACE(amt->dev);
tlen = amt->dev->needed_tailroom;
len = hlen + tlen + sizeof(*iph) + sizeof(*udph) + sizeof(*amtrh);
skb = netdev_alloc_skb_ip_align(amt->dev, len);
if (!skb) {
ip_rt_put(rt);
amt->dev->stats.tx_errors++;
goto out;
}
skb->priority = TC_PRIO_CONTROL;
skb_dst_set(skb, &rt->dst);
len = sizeof(*iph) + sizeof(*udph) + sizeof(*amtrh);
skb_reset_network_header(skb);
skb_put(skb, len);
amtrh = skb_pull(skb, sizeof(*iph) + sizeof(*udph));
amtrh->version = 0;
amtrh->type = AMT_MSG_REQUEST;
amtrh->reserved1 = 0;
amtrh->p = v6;
amtrh->reserved2 = 0;
amtrh->nonce = amt->nonce;
skb_push(skb, sizeof(*udph));
skb_reset_transport_header(skb);
udph = udp_hdr(skb);
udph->source = amt->gw_port;
udph->dest = amt->relay_port;
udph->len = htons(sizeof(*amtrh) + sizeof(*udph));
udph->check = 0;
offset = skb_transport_offset(skb);
skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
udph->check = csum_tcpudp_magic(amt->local_ip, amt->remote_ip,
sizeof(*udph) + sizeof(*amtrh),
IPPROTO_UDP, skb->csum);
skb_push(skb, sizeof(*iph));
iph = ip_hdr(skb);
iph->version = 4;
iph->ihl = (sizeof(struct iphdr)) >> 2;
iph->tos = AMT_TOS;
iph->frag_off = 0;
iph->ttl = ip4_dst_hoplimit(&rt->dst);
iph->daddr = amt->remote_ip;
iph->saddr = amt->local_ip;
iph->protocol = IPPROTO_UDP;
iph->tot_len = htons(len);
skb->ip_summed = CHECKSUM_NONE;
ip_select_ident(amt->net, skb, NULL);
ip_send_check(iph);
err = ip_local_out(amt->net, sock->sk, skb);
if (unlikely(net_xmit_eval(err)))
amt->dev->stats.tx_errors++;
out:
rcu_read_unlock();
}
static void amt_send_igmp_gq(struct amt_dev *amt,
struct amt_tunnel_list *tunnel)
{
struct sk_buff *skb;
skb = amt_build_igmp_gq(amt);
if (!skb)
return;
amt_skb_cb(skb)->tunnel = tunnel;
dev_queue_xmit(skb);
}
#if IS_ENABLED(CONFIG_IPV6)
static struct sk_buff *amt_build_mld_gq(struct amt_dev *amt)
{
u8 ra[AMT_IP6HDR_OPTS] = { IPPROTO_ICMPV6, 0, IPV6_TLV_ROUTERALERT,
2, 0, 0, IPV6_TLV_PAD1, IPV6_TLV_PAD1 };
int hlen = LL_RESERVED_SPACE(amt->dev);
int tlen = amt->dev->needed_tailroom;
struct mld2_query *mld2q;
void *csum_start = NULL;
struct ipv6hdr *ip6h;
struct sk_buff *skb;
struct ethhdr *eth;
u32 len;
len = hlen + tlen + sizeof(*ip6h) + sizeof(ra) + sizeof(*mld2q);
skb = netdev_alloc_skb_ip_align(amt->dev, len);
if (!skb)
return NULL;
skb_reserve(skb, hlen);
skb_push(skb, sizeof(*eth));
skb_reset_mac_header(skb);
eth = eth_hdr(skb);
skb->priority = TC_PRIO_CONTROL;
skb->protocol = htons(ETH_P_IPV6);
skb_put_zero(skb, sizeof(*ip6h));
skb_put_data(skb, ra, sizeof(ra));
skb_put_zero(skb, sizeof(*mld2q));
skb_pull(skb, sizeof(*eth));
skb_reset_network_header(skb);
ip6h = ipv6_hdr(skb);
ip6h->payload_len = htons(sizeof(ra) + sizeof(*mld2q));
ip6h->nexthdr = NEXTHDR_HOP;
ip6h->hop_limit = 1;
ip6h->daddr = mld2_all_node;
ip6_flow_hdr(ip6h, 0, 0);
if (ipv6_dev_get_saddr(amt->net, amt->dev, &ip6h->daddr, 0,
&ip6h->saddr)) {
amt->dev->stats.tx_errors++;
kfree_skb(skb);
return NULL;
}
eth->h_proto = htons(ETH_P_IPV6);
ether_addr_copy(eth->h_source, amt->dev->dev_addr);
ipv6_eth_mc_map(&mld2_all_node, eth->h_dest);
skb_pull(skb, sizeof(*ip6h) + sizeof(ra));
skb_reset_transport_header(skb);
mld2q = (struct mld2_query *)icmp6_hdr(skb);
mld2q->mld2q_mrc = htons(1);
mld2q->mld2q_type = ICMPV6_MGM_QUERY;
mld2q->mld2q_code = 0;
mld2q->mld2q_cksum = 0;
mld2q->mld2q_resv1 = 0;
mld2q->mld2q_resv2 = 0;
mld2q->mld2q_suppress = 0;
mld2q->mld2q_qrv = amt->qrv;
mld2q->mld2q_nsrcs = 0;
mld2q->mld2q_qqic = amt->qi;
csum_start = (void *)mld2q;
mld2q->mld2q_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
sizeof(*mld2q),
IPPROTO_ICMPV6,
csum_partial(csum_start,
sizeof(*mld2q), 0));
skb->ip_summed = CHECKSUM_NONE;
skb_push(skb, sizeof(*eth) + sizeof(*ip6h) + sizeof(ra));
return skb;
}
static void amt_send_mld_gq(struct amt_dev *amt, struct amt_tunnel_list *tunnel)
{
struct sk_buff *skb;
skb = amt_build_mld_gq(amt);
if (!skb)
return;
amt_skb_cb(skb)->tunnel = tunnel;
dev_queue_xmit(skb);
}
#else
static void amt_send_mld_gq(struct amt_dev *amt, struct amt_tunnel_list *tunnel)
{
}
#endif
static bool amt_queue_event(struct amt_dev *amt, enum amt_event event,
struct sk_buff *skb)
{
int index;
spin_lock_bh(&amt->lock);
if (amt->nr_events >= AMT_MAX_EVENTS) {
spin_unlock_bh(&amt->lock);
return 1;
}
index = (amt->event_idx + amt->nr_events) % AMT_MAX_EVENTS;
amt->events[index].event = event;
amt->events[index].skb = skb;
amt->nr_events++;
amt->event_idx %= AMT_MAX_EVENTS;
queue_work(amt_wq, &amt->event_wq);
spin_unlock_bh(&amt->lock);
return 0;
}
static void amt_secret_work(struct work_struct *work)
{
struct amt_dev *amt = container_of(to_delayed_work(work),
struct amt_dev,
secret_wq);
spin_lock_bh(&amt->lock);
get_random_bytes(&amt->key, sizeof(siphash_key_t));
spin_unlock_bh(&amt->lock);
mod_delayed_work(amt_wq, &amt->secret_wq,
msecs_to_jiffies(AMT_SECRET_TIMEOUT));
}
static void amt_event_send_discovery(struct amt_dev *amt)
{
if (amt->status > AMT_STATUS_SENT_DISCOVERY)
goto out;
get_random_bytes(&amt->nonce, sizeof(__be32));
amt_send_discovery(amt);
out:
mod_delayed_work(amt_wq, &amt->discovery_wq,
msecs_to_jiffies(AMT_DISCOVERY_TIMEOUT));
}
static void amt_discovery_work(struct work_struct *work)
{
struct amt_dev *amt = container_of(to_delayed_work(work),
struct amt_dev,
discovery_wq);
if (amt_queue_event(amt, AMT_EVENT_SEND_DISCOVERY, NULL))
mod_delayed_work(amt_wq, &amt->discovery_wq,
msecs_to_jiffies(AMT_DISCOVERY_TIMEOUT));
}
static void amt_event_send_request(struct amt_dev *amt)
{
u32 exp;
if (amt->status < AMT_STATUS_RECEIVED_ADVERTISEMENT)
goto out;
if (amt->req_cnt > AMT_MAX_REQ_COUNT) {
netdev_dbg(amt->dev, "Gateway is not ready");
amt->qi = AMT_INIT_REQ_TIMEOUT;
WRITE_ONCE(amt->ready4, false);
WRITE_ONCE(amt->ready6, false);
amt->remote_ip = 0;
amt_update_gw_status(amt, AMT_STATUS_INIT, false);
amt->req_cnt = 0;
amt->nonce = 0;
goto out;
}
if (!amt->req_cnt) {
WRITE_ONCE(amt->ready4, false);
WRITE_ONCE(amt->ready6, false);
get_random_bytes(&amt->nonce, sizeof(__be32));
}
amt_send_request(amt, false);
amt_send_request(amt, true);
amt_update_gw_status(amt, AMT_STATUS_SENT_REQUEST, true);
amt->req_cnt++;
out:
exp = min_t(u32, (1 * (1 << amt->req_cnt)), AMT_MAX_REQ_TIMEOUT);
mod_delayed_work(amt_wq, &amt->req_wq, msecs_to_jiffies(exp * 1000));
}
static void amt_req_work(struct work_struct *work)
{
struct amt_dev *amt = container_of(to_delayed_work(work),
struct amt_dev,
req_wq);
if (amt_queue_event(amt, AMT_EVENT_SEND_REQUEST, NULL))
mod_delayed_work(amt_wq, &amt->req_wq,
msecs_to_jiffies(100));
}
static bool amt_send_membership_update(struct amt_dev *amt,
struct sk_buff *skb,
bool v6)
{
struct amt_header_membership_update *amtmu;