linuxdebug/net/xfrm/espintcp.c

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2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0
#include <net/tcp.h>
#include <net/strparser.h>
#include <net/xfrm.h>
#include <net/esp.h>
#include <net/espintcp.h>
#include <linux/skmsg.h>
#include <net/inet_common.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6_stubs.h>
#endif
static void handle_nonesp(struct espintcp_ctx *ctx, struct sk_buff *skb,
struct sock *sk)
{
if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf ||
!sk_rmem_schedule(sk, skb, skb->truesize)) {
XFRM_INC_STATS(sock_net(sk), LINUX_MIB_XFRMINERROR);
kfree_skb(skb);
return;
}
skb_set_owner_r(skb, sk);
memset(skb->cb, 0, sizeof(skb->cb));
skb_queue_tail(&ctx->ike_queue, skb);
ctx->saved_data_ready(sk);
}
static void handle_esp(struct sk_buff *skb, struct sock *sk)
{
struct tcp_skb_cb *tcp_cb = (struct tcp_skb_cb *)skb->cb;
skb_reset_transport_header(skb);
/* restore IP CB, we need at least IP6CB->nhoff */
memmove(skb->cb, &tcp_cb->header, sizeof(tcp_cb->header));
rcu_read_lock();
skb->dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif);
local_bh_disable();
#if IS_ENABLED(CONFIG_IPV6)
if (sk->sk_family == AF_INET6)
ipv6_stub->xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP);
else
#endif
xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, TCP_ENCAP_ESPINTCP);
local_bh_enable();
rcu_read_unlock();
}
static void espintcp_rcv(struct strparser *strp, struct sk_buff *skb)
{
struct espintcp_ctx *ctx = container_of(strp, struct espintcp_ctx,
strp);
struct strp_msg *rxm = strp_msg(skb);
int len = rxm->full_len - 2;
u32 nonesp_marker;
int err;
/* keepalive packet? */
if (unlikely(len == 1)) {
u8 data;
err = skb_copy_bits(skb, rxm->offset + 2, &data, 1);
if (err < 0) {
XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR);
kfree_skb(skb);
return;
}
if (data == 0xff) {
kfree_skb(skb);
return;
}
}
/* drop other short messages */
if (unlikely(len <= sizeof(nonesp_marker))) {
XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR);
kfree_skb(skb);
return;
}
err = skb_copy_bits(skb, rxm->offset + 2, &nonesp_marker,
sizeof(nonesp_marker));
if (err < 0) {
XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINHDRERROR);
kfree_skb(skb);
return;
}
/* remove header, leave non-ESP marker/SPI */
if (!pskb_pull(skb, rxm->offset + 2)) {
XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR);
kfree_skb(skb);
return;
}
if (pskb_trim(skb, rxm->full_len - 2) != 0) {
XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR);
kfree_skb(skb);
return;
}
if (nonesp_marker == 0)
handle_nonesp(ctx, skb, strp->sk);
else
handle_esp(skb, strp->sk);
}
static int espintcp_parse(struct strparser *strp, struct sk_buff *skb)
{
struct strp_msg *rxm = strp_msg(skb);
__be16 blen;
u16 len;
int err;
if (skb->len < rxm->offset + 2)
return 0;
err = skb_copy_bits(skb, rxm->offset, &blen, sizeof(blen));
if (err < 0)
return err;
len = be16_to_cpu(blen);
if (len < 2)
return -EINVAL;
return len;
}
static int espintcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
int flags, int *addr_len)
{
struct espintcp_ctx *ctx = espintcp_getctx(sk);
struct sk_buff *skb;
int err = 0;
int copied;
int off = 0;
skb = __skb_recv_datagram(sk, &ctx->ike_queue, flags, &off, &err);
if (!skb) {
if (err == -EAGAIN && sk->sk_shutdown & RCV_SHUTDOWN)
return 0;
return err;
}
copied = len;
if (copied > skb->len)
copied = skb->len;
else if (copied < skb->len)
msg->msg_flags |= MSG_TRUNC;
err = skb_copy_datagram_msg(skb, 0, msg, copied);
if (unlikely(err)) {
kfree_skb(skb);
return err;
}
if (flags & MSG_TRUNC)
copied = skb->len;
kfree_skb(skb);
return copied;
}
int espintcp_queue_out(struct sock *sk, struct sk_buff *skb)
{
struct espintcp_ctx *ctx = espintcp_getctx(sk);
if (skb_queue_len(&ctx->out_queue) >= READ_ONCE(netdev_max_backlog))
return -ENOBUFS;
__skb_queue_tail(&ctx->out_queue, skb);
return 0;
}
EXPORT_SYMBOL_GPL(espintcp_queue_out);
/* espintcp length field is 2B and length includes the length field's size */
#define MAX_ESPINTCP_MSG (((1 << 16) - 1) - 2)
static int espintcp_sendskb_locked(struct sock *sk, struct espintcp_msg *emsg,
int flags)
{
do {
int ret;
ret = skb_send_sock_locked(sk, emsg->skb,
emsg->offset, emsg->len);
if (ret < 0)
return ret;
emsg->len -= ret;
emsg->offset += ret;
} while (emsg->len > 0);
kfree_skb(emsg->skb);
memset(emsg, 0, sizeof(*emsg));
return 0;
}
static int espintcp_sendskmsg_locked(struct sock *sk,
struct espintcp_msg *emsg, int flags)
{
struct sk_msg *skmsg = &emsg->skmsg;
struct scatterlist *sg;
int done = 0;
int ret;
flags |= MSG_SENDPAGE_NOTLAST;
sg = &skmsg->sg.data[skmsg->sg.start];
do {
size_t size = sg->length - emsg->offset;
int offset = sg->offset + emsg->offset;
struct page *p;
emsg->offset = 0;
if (sg_is_last(sg))
flags &= ~MSG_SENDPAGE_NOTLAST;
p = sg_page(sg);
retry:
ret = do_tcp_sendpages(sk, p, offset, size, flags);
if (ret < 0) {
emsg->offset = offset - sg->offset;
skmsg->sg.start += done;
return ret;
}
if (ret != size) {
offset += ret;
size -= ret;
goto retry;
}
done++;
put_page(p);
sk_mem_uncharge(sk, sg->length);
sg = sg_next(sg);
} while (sg);
memset(emsg, 0, sizeof(*emsg));
return 0;
}
static int espintcp_push_msgs(struct sock *sk, int flags)
{
struct espintcp_ctx *ctx = espintcp_getctx(sk);
struct espintcp_msg *emsg = &ctx->partial;
int err;
if (!emsg->len)
return 0;
if (ctx->tx_running)
return -EAGAIN;
ctx->tx_running = 1;
if (emsg->skb)
err = espintcp_sendskb_locked(sk, emsg, flags);
else
err = espintcp_sendskmsg_locked(sk, emsg, flags);
if (err == -EAGAIN) {
ctx->tx_running = 0;
return flags & MSG_DONTWAIT ? -EAGAIN : 0;
}
if (!err)
memset(emsg, 0, sizeof(*emsg));
ctx->tx_running = 0;
return err;
}
int espintcp_push_skb(struct sock *sk, struct sk_buff *skb)
{
struct espintcp_ctx *ctx = espintcp_getctx(sk);
struct espintcp_msg *emsg = &ctx->partial;
unsigned int len;
int offset;
if (sk->sk_state != TCP_ESTABLISHED) {
kfree_skb(skb);
return -ECONNRESET;
}
offset = skb_transport_offset(skb);
len = skb->len - offset;
espintcp_push_msgs(sk, 0);
if (emsg->len) {
kfree_skb(skb);
return -ENOBUFS;
}
skb_set_owner_w(skb, sk);
emsg->offset = offset;
emsg->len = len;
emsg->skb = skb;
espintcp_push_msgs(sk, 0);
return 0;
}
EXPORT_SYMBOL_GPL(espintcp_push_skb);
static int espintcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
{
long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
struct espintcp_ctx *ctx = espintcp_getctx(sk);
struct espintcp_msg *emsg = &ctx->partial;
struct iov_iter pfx_iter;
struct kvec pfx_iov = {};
size_t msglen = size + 2;
char buf[2] = {0};
int err, end;
if (msg->msg_flags & ~MSG_DONTWAIT)
return -EOPNOTSUPP;
if (size > MAX_ESPINTCP_MSG)
return -EMSGSIZE;
if (msg->msg_controllen)
return -EOPNOTSUPP;
lock_sock(sk);
err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT);
if (err < 0) {
if (err != -EAGAIN || !(msg->msg_flags & MSG_DONTWAIT))
err = -ENOBUFS;
goto unlock;
}
sk_msg_init(&emsg->skmsg);
while (1) {
/* only -ENOMEM is possible since we don't coalesce */
err = sk_msg_alloc(sk, &emsg->skmsg, msglen, 0);
if (!err)
break;
err = sk_stream_wait_memory(sk, &timeo);
if (err)
goto fail;
}
*((__be16 *)buf) = cpu_to_be16(msglen);
pfx_iov.iov_base = buf;
pfx_iov.iov_len = sizeof(buf);
iov_iter_kvec(&pfx_iter, ITER_SOURCE, &pfx_iov, 1, pfx_iov.iov_len);
err = sk_msg_memcopy_from_iter(sk, &pfx_iter, &emsg->skmsg,
pfx_iov.iov_len);
if (err < 0)
goto fail;
err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, &emsg->skmsg, size);
if (err < 0)
goto fail;
end = emsg->skmsg.sg.end;
emsg->len = size;
sk_msg_iter_var_prev(end);
sg_mark_end(sk_msg_elem(&emsg->skmsg, end));
tcp_rate_check_app_limited(sk);
err = espintcp_push_msgs(sk, msg->msg_flags & MSG_DONTWAIT);
/* this message could be partially sent, keep it */
release_sock(sk);
return size;
fail:
sk_msg_free(sk, &emsg->skmsg);
memset(emsg, 0, sizeof(*emsg));
unlock:
release_sock(sk);
return err;
}
static struct proto espintcp_prot __ro_after_init;
static struct proto_ops espintcp_ops __ro_after_init;
static struct proto espintcp6_prot;
static struct proto_ops espintcp6_ops;
static DEFINE_MUTEX(tcpv6_prot_mutex);
static void espintcp_data_ready(struct sock *sk)
{
struct espintcp_ctx *ctx = espintcp_getctx(sk);
strp_data_ready(&ctx->strp);
}
static void espintcp_tx_work(struct work_struct *work)
{
struct espintcp_ctx *ctx = container_of(work,
struct espintcp_ctx, work);
struct sock *sk = ctx->strp.sk;
lock_sock(sk);
if (!ctx->tx_running)
espintcp_push_msgs(sk, 0);
release_sock(sk);
}
static void espintcp_write_space(struct sock *sk)
{
struct espintcp_ctx *ctx = espintcp_getctx(sk);
schedule_work(&ctx->work);
ctx->saved_write_space(sk);
}
static void espintcp_destruct(struct sock *sk)
{
struct espintcp_ctx *ctx = espintcp_getctx(sk);
ctx->saved_destruct(sk);
kfree(ctx);
}
bool tcp_is_ulp_esp(struct sock *sk)
{
return sk->sk_prot == &espintcp_prot || sk->sk_prot == &espintcp6_prot;
}
EXPORT_SYMBOL_GPL(tcp_is_ulp_esp);
static void build_protos(struct proto *espintcp_prot,
struct proto_ops *espintcp_ops,
const struct proto *orig_prot,
const struct proto_ops *orig_ops);
static int espintcp_init_sk(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct strp_callbacks cb = {
.rcv_msg = espintcp_rcv,
.parse_msg = espintcp_parse,
};
struct espintcp_ctx *ctx;
int err;
/* sockmap is not compatible with espintcp */
if (sk->sk_user_data)
return -EBUSY;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
err = strp_init(&ctx->strp, sk, &cb);
if (err)
goto free;
__sk_dst_reset(sk);
strp_check_rcv(&ctx->strp);
skb_queue_head_init(&ctx->ike_queue);
skb_queue_head_init(&ctx->out_queue);
if (sk->sk_family == AF_INET) {
sk->sk_prot = &espintcp_prot;
sk->sk_socket->ops = &espintcp_ops;
} else {
mutex_lock(&tcpv6_prot_mutex);
if (!espintcp6_prot.recvmsg)
build_protos(&espintcp6_prot, &espintcp6_ops, sk->sk_prot, sk->sk_socket->ops);
mutex_unlock(&tcpv6_prot_mutex);
sk->sk_prot = &espintcp6_prot;
sk->sk_socket->ops = &espintcp6_ops;
}
ctx->saved_data_ready = sk->sk_data_ready;
ctx->saved_write_space = sk->sk_write_space;
ctx->saved_destruct = sk->sk_destruct;
sk->sk_data_ready = espintcp_data_ready;
sk->sk_write_space = espintcp_write_space;
sk->sk_destruct = espintcp_destruct;
rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
INIT_WORK(&ctx->work, espintcp_tx_work);
/* avoid using task_frag */
sk->sk_allocation = GFP_ATOMIC;
return 0;
free:
kfree(ctx);
return err;
}
static void espintcp_release(struct sock *sk)
{
struct espintcp_ctx *ctx = espintcp_getctx(sk);
struct sk_buff_head queue;
struct sk_buff *skb;
__skb_queue_head_init(&queue);
skb_queue_splice_init(&ctx->out_queue, &queue);
while ((skb = __skb_dequeue(&queue)))
espintcp_push_skb(sk, skb);
tcp_release_cb(sk);
}
static void espintcp_close(struct sock *sk, long timeout)
{
struct espintcp_ctx *ctx = espintcp_getctx(sk);
struct espintcp_msg *emsg = &ctx->partial;
strp_stop(&ctx->strp);
sk->sk_prot = &tcp_prot;
barrier();
cancel_work_sync(&ctx->work);
strp_done(&ctx->strp);
skb_queue_purge(&ctx->out_queue);
skb_queue_purge(&ctx->ike_queue);
if (emsg->len) {
if (emsg->skb)
kfree_skb(emsg->skb);
else
sk_msg_free(sk, &emsg->skmsg);
}
tcp_close(sk, timeout);
}
static __poll_t espintcp_poll(struct file *file, struct socket *sock,
poll_table *wait)
{
__poll_t mask = datagram_poll(file, sock, wait);
struct sock *sk = sock->sk;
struct espintcp_ctx *ctx = espintcp_getctx(sk);
if (!skb_queue_empty(&ctx->ike_queue))
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
static void build_protos(struct proto *espintcp_prot,
struct proto_ops *espintcp_ops,
const struct proto *orig_prot,
const struct proto_ops *orig_ops)
{
memcpy(espintcp_prot, orig_prot, sizeof(struct proto));
memcpy(espintcp_ops, orig_ops, sizeof(struct proto_ops));
espintcp_prot->sendmsg = espintcp_sendmsg;
espintcp_prot->recvmsg = espintcp_recvmsg;
espintcp_prot->close = espintcp_close;
espintcp_prot->release_cb = espintcp_release;
espintcp_ops->poll = espintcp_poll;
}
static struct tcp_ulp_ops espintcp_ulp __read_mostly = {
.name = "espintcp",
.owner = THIS_MODULE,
.init = espintcp_init_sk,
};
void __init espintcp_init(void)
{
build_protos(&espintcp_prot, &espintcp_ops, &tcp_prot, &inet_stream_ops);
tcp_register_ulp(&espintcp_ulp);
}