mirror of https://github.com/OpenIPC/firmware.git
455 lines
12 KiB
Diff
455 lines
12 KiB
Diff
diff -drupN a/drivers/net/ppp/pppolac.c b/drivers/net/ppp/pppolac.c
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--- a/drivers/net/ppp/pppolac.c 1970-01-01 03:00:00.000000000 +0300
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+++ b/drivers/net/ppp/pppolac.c 2022-06-12 05:28:14.000000000 +0300
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@@ -0,0 +1,450 @@
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+/* drivers/net/pppolac.c
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+ *
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+ * Driver for PPP on L2TP Access Concentrator / PPPoLAC Socket (RFC 2661)
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+ *
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+ * Copyright (C) 2009 Google, Inc.
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+ *
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+ * This software is licensed under the terms of the GNU General Public
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+ * License version 2, as published by the Free Software Foundation, and
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+ * may be copied, distributed, and modified under those terms.
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+ *
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+ * This program is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ */
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+
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+/* This driver handles L2TP data packets between a UDP socket and a PPP channel.
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+ * The socket must keep connected, and only one session per socket is permitted.
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+ * Sequencing of outgoing packets is controlled by LNS. Incoming packets with
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+ * sequences are reordered within a sliding window of one second. Currently
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+ * reordering only happens when a packet is received. It is done for simplicity
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+ * since no additional locks or threads are required. This driver only works on
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+ * IPv4 due to the lack of UDP encapsulation support in IPv6. */
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+
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+#include <linux/module.h>
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+#include <linux/jiffies.h>
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+#include <linux/workqueue.h>
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+#include <linux/skbuff.h>
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+#include <linux/file.h>
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+#include <linux/netdevice.h>
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+#include <linux/net.h>
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+#include <linux/udp.h>
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+#include <linux/ppp_defs.h>
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+#include <linux/if_ppp.h>
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+#include <linux/if_pppox.h>
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+#include <linux/ppp_channel.h>
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+#include <net/tcp_states.h>
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+#include <asm/uaccess.h>
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+
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+#define L2TP_CONTROL_BIT 0x80
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+#define L2TP_LENGTH_BIT 0x40
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+#define L2TP_SEQUENCE_BIT 0x08
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+#define L2TP_OFFSET_BIT 0x02
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+#define L2TP_VERSION 0x02
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+#define L2TP_VERSION_MASK 0x0F
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+
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+#define PPP_ADDR 0xFF
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+#define PPP_CTRL 0x03
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+
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+union unaligned {
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+ __u32 u32;
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+} __attribute__((packed));
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+
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+static inline union unaligned *unaligned(void *ptr)
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+{
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+ return (union unaligned *)ptr;
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+}
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+
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+struct meta {
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+ __u32 sequence;
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+ __u32 timestamp;
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+};
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+
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+static inline struct meta *skb_meta(struct sk_buff *skb)
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+{
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+ return (struct meta *)skb->cb;
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+}
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+
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+/******************************************************************************/
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+
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+static int pppolac_recv_core(struct sock *sk_udp, struct sk_buff *skb)
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+{
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+ struct sock *sk = (struct sock *)sk_udp->sk_user_data;
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+ struct pppolac_opt *opt = &pppox_sk(sk)->proto.lac;
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+ struct meta *meta = skb_meta(skb);
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+ __u32 now = jiffies;
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+ __u8 bits;
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+ __u8 *ptr;
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+
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+ /* Drop the packet if L2TP header is missing. */
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+ if (skb->len < sizeof(struct udphdr) + 6)
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+ goto drop;
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+
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+ /* Put it back if it is a control packet. */
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+ if (skb->data[sizeof(struct udphdr)] & L2TP_CONTROL_BIT)
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+ return opt->backlog_rcv(sk_udp, skb);
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+
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+ /* Skip UDP header. */
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+ skb_pull(skb, sizeof(struct udphdr));
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+
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+ /* Check the version. */
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+ if ((skb->data[1] & L2TP_VERSION_MASK) != L2TP_VERSION)
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+ goto drop;
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+ bits = skb->data[0];
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+ ptr = &skb->data[2];
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+
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+ /* Check the length if it is present. */
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+ if (bits & L2TP_LENGTH_BIT) {
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+ if ((ptr[0] << 8 | ptr[1]) != skb->len)
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+ goto drop;
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+ ptr += 2;
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+ }
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+
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+ /* Skip all fields including optional ones. */
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+ if (!skb_pull(skb, 6 + (bits & L2TP_SEQUENCE_BIT ? 4 : 0) +
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+ (bits & L2TP_LENGTH_BIT ? 2 : 0) +
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+ (bits & L2TP_OFFSET_BIT ? 2 : 0)))
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+ goto drop;
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+
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+ /* Skip the offset padding if it is present. */
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+ if (bits & L2TP_OFFSET_BIT &&
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+ !skb_pull(skb, skb->data[-2] << 8 | skb->data[-1]))
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+ goto drop;
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+
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+ /* Check the tunnel and the session. */
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+ if (unaligned(ptr)->u32 != opt->local)
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+ goto drop;
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+
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+ /* Check the sequence if it is present. */
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+ if (bits & L2TP_SEQUENCE_BIT) {
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+ meta->sequence = ptr[4] << 8 | ptr[5];
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+ if ((__s16)(meta->sequence - opt->recv_sequence) < 0)
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+ goto drop;
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+ }
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+
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+ /* Skip PPP address and control if they are present. */
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+ if (skb->len >= 2 && skb->data[0] == PPP_ADDR &&
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+ skb->data[1] == PPP_CTRL)
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+ skb_pull(skb, 2);
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+
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+ /* Fix PPP protocol if it is compressed. */
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+ if (skb->len >= 1 && skb->data[0] & 1)
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+ skb_push(skb, 1)[0] = 0;
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+
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+ /* Drop the packet if PPP protocol is missing. */
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+ if (skb->len < 2)
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+ goto drop;
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+
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+ /* Perform reordering if sequencing is enabled. */
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+ atomic_set(&opt->sequencing, bits & L2TP_SEQUENCE_BIT);
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+ if (bits & L2TP_SEQUENCE_BIT) {
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+ struct sk_buff *skb1;
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+
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+ /* Insert the packet into receive queue in order. */
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+ skb_set_owner_r(skb, sk);
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+ skb_queue_walk(&sk->sk_receive_queue, skb1) {
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+ struct meta *meta1 = skb_meta(skb1);
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+ __s16 order = meta->sequence - meta1->sequence;
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+ if (order == 0)
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+ goto drop;
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+ if (order < 0) {
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+ meta->timestamp = meta1->timestamp;
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+ skb_insert(skb1, skb, &sk->sk_receive_queue);
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+ skb = NULL;
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+ break;
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+ }
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+ }
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+ if (skb) {
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+ meta->timestamp = now;
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+ skb_queue_tail(&sk->sk_receive_queue, skb);
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+ }
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+
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+ /* Remove packets from receive queue as long as
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+ * 1. the receive buffer is full,
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+ * 2. they are queued longer than one second, or
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+ * 3. there are no missing packets before them. */
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+ skb_queue_walk_safe(&sk->sk_receive_queue, skb, skb1) {
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+ meta = skb_meta(skb);
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+ if (atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf &&
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+ now - meta->timestamp < HZ &&
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+ meta->sequence != opt->recv_sequence)
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+ break;
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+ skb_unlink(skb, &sk->sk_receive_queue);
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+ opt->recv_sequence = (__u16)(meta->sequence + 1);
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+ skb_orphan(skb);
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+ ppp_input(&pppox_sk(sk)->chan, skb);
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+ }
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+ return NET_RX_SUCCESS;
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+ }
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+
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+ /* Flush receive queue if sequencing is disabled. */
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+ skb_queue_purge(&sk->sk_receive_queue);
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+ skb_orphan(skb);
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+ ppp_input(&pppox_sk(sk)->chan, skb);
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+ return NET_RX_SUCCESS;
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+drop:
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+ kfree_skb(skb);
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+ return NET_RX_DROP;
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+}
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+
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+static int pppolac_recv(struct sock *sk_udp, struct sk_buff *skb)
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+{
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+ sock_hold(sk_udp);
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+ sk_receive_skb(sk_udp, skb, 0);
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+ return 0;
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+}
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+
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+static struct sk_buff_head delivery_queue;
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+
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+static void pppolac_xmit_core(struct work_struct *delivery_work)
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+{
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+ mm_segment_t old_fs = get_fs();
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+ struct sk_buff *skb;
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+
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+ set_fs(KERNEL_DS);
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+ while ((skb = skb_dequeue(&delivery_queue))) {
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+ struct sock *sk_udp = skb->sk;
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+ struct kvec iov = {.iov_base = skb->data, .iov_len = skb->len};
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+ struct msghdr msg = {
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+ .msg_flags = MSG_NOSIGNAL | MSG_DONTWAIT,
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+ };
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+
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+ iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, &iov, 1,
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+ skb->len);
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+ sk_udp->sk_prot->sendmsg(sk_udp, &msg, skb->len);
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+ kfree_skb(skb);
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+ }
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+ set_fs(old_fs);
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+}
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+
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+static DECLARE_WORK(delivery_work, pppolac_xmit_core);
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+
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+static int pppolac_xmit(struct ppp_channel *chan, struct sk_buff *skb)
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+{
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+ struct sock *sk_udp = (struct sock *)chan->private;
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+ struct pppolac_opt *opt = &pppox_sk(sk_udp->sk_user_data)->proto.lac;
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+
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+ /* Install PPP address and control. */
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+ skb_push(skb, 2);
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+ skb->data[0] = PPP_ADDR;
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+ skb->data[1] = PPP_CTRL;
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+
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+ /* Install L2TP header. */
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+ if (atomic_read(&opt->sequencing)) {
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+ skb_push(skb, 10);
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+ skb->data[0] = L2TP_SEQUENCE_BIT;
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+ skb->data[6] = opt->xmit_sequence >> 8;
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+ skb->data[7] = opt->xmit_sequence;
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+ skb->data[8] = 0;
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+ skb->data[9] = 0;
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+ opt->xmit_sequence++;
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+ } else {
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+ skb_push(skb, 6);
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+ skb->data[0] = 0;
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+ }
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+ skb->data[1] = L2TP_VERSION;
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+ unaligned(&skb->data[2])->u32 = opt->remote;
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+
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+ /* Now send the packet via the delivery queue. */
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+ skb_set_owner_w(skb, sk_udp);
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+ skb_queue_tail(&delivery_queue, skb);
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+ schedule_work(&delivery_work);
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+ return 1;
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+}
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+
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+/******************************************************************************/
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+
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+static struct ppp_channel_ops pppolac_channel_ops = {
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+ .start_xmit = pppolac_xmit,
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+};
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+
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+static int pppolac_connect(struct socket *sock, struct sockaddr *useraddr,
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+ int addrlen, int flags)
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+{
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+ struct sock *sk = sock->sk;
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+ struct pppox_sock *po = pppox_sk(sk);
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+ struct sockaddr_pppolac *addr = (struct sockaddr_pppolac *)useraddr;
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+ struct socket *sock_udp = NULL;
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+ struct sock *sk_udp;
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+ int error;
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+
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+ if (addrlen != sizeof(struct sockaddr_pppolac) ||
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+ !addr->local.tunnel || !addr->local.session ||
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+ !addr->remote.tunnel || !addr->remote.session) {
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+ return -EINVAL;
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+ }
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+
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+ lock_sock(sk);
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+ error = -EALREADY;
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+ if (sk->sk_state != PPPOX_NONE)
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+ goto out;
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+
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+ sock_udp = sockfd_lookup(addr->udp_socket, &error);
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+ if (!sock_udp)
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+ goto out;
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+ sk_udp = sock_udp->sk;
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+ lock_sock(sk_udp);
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+
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+ /* Remove this check when IPv6 supports UDP encapsulation. */
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+ error = -EAFNOSUPPORT;
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+ if (sk_udp->sk_family != AF_INET)
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+ goto out;
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+ error = -EPROTONOSUPPORT;
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+ if (sk_udp->sk_protocol != IPPROTO_UDP)
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+ goto out;
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+ error = -EDESTADDRREQ;
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+ if (sk_udp->sk_state != TCP_ESTABLISHED)
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+ goto out;
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+ error = -EBUSY;
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+ if (udp_sk(sk_udp)->encap_type || sk_udp->sk_user_data)
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+ goto out;
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+ if (!sk_udp->sk_bound_dev_if) {
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+ struct dst_entry *dst = sk_dst_get(sk_udp);
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+ error = -ENODEV;
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+ if (!dst)
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+ goto out;
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+ sk_udp->sk_bound_dev_if = dst->dev->ifindex;
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+ dst_release(dst);
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+ }
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+
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+ po->chan.hdrlen = 12;
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+ po->chan.private = sk_udp;
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+ po->chan.ops = &pppolac_channel_ops;
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+ po->chan.mtu = PPP_MRU - 80;
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+ po->proto.lac.local = unaligned(&addr->local)->u32;
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+ po->proto.lac.remote = unaligned(&addr->remote)->u32;
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+ atomic_set(&po->proto.lac.sequencing, 1);
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+ po->proto.lac.backlog_rcv = sk_udp->sk_backlog_rcv;
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+
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+ error = ppp_register_channel(&po->chan);
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+ if (error)
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+ goto out;
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+
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+ sk->sk_state = PPPOX_CONNECTED;
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+ udp_sk(sk_udp)->encap_type = UDP_ENCAP_L2TPINUDP;
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+ udp_sk(sk_udp)->encap_rcv = pppolac_recv;
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+ sk_udp->sk_backlog_rcv = pppolac_recv_core;
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+ sk_udp->sk_user_data = sk;
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+out:
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+ if (sock_udp) {
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+ release_sock(sk_udp);
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+ if (error)
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+ sockfd_put(sock_udp);
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+ }
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+ release_sock(sk);
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+ return error;
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+}
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+
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+static int pppolac_release(struct socket *sock)
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+{
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+ struct sock *sk = sock->sk;
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+
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+ if (!sk)
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+ return 0;
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+
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+ lock_sock(sk);
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+ if (sock_flag(sk, SOCK_DEAD)) {
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+ release_sock(sk);
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+ return -EBADF;
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+ }
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+
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+ if (sk->sk_state != PPPOX_NONE) {
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+ struct sock *sk_udp = (struct sock *)pppox_sk(sk)->chan.private;
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+ lock_sock(sk_udp);
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+ skb_queue_purge(&sk->sk_receive_queue);
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+ pppox_unbind_sock(sk);
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+ udp_sk(sk_udp)->encap_type = 0;
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+ udp_sk(sk_udp)->encap_rcv = NULL;
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+ sk_udp->sk_backlog_rcv = pppox_sk(sk)->proto.lac.backlog_rcv;
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+ sk_udp->sk_user_data = NULL;
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+ release_sock(sk_udp);
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+ sockfd_put(sk_udp->sk_socket);
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+ }
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+
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+ sock_orphan(sk);
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+ sock->sk = NULL;
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+ release_sock(sk);
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+ sock_put(sk);
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+ return 0;
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+}
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+
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+/******************************************************************************/
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+
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+static struct proto pppolac_proto = {
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+ .name = "PPPOLAC",
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+ .owner = THIS_MODULE,
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+ .obj_size = sizeof(struct pppox_sock),
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+};
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+
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+static struct proto_ops pppolac_proto_ops = {
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+ .family = PF_PPPOX,
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+ .owner = THIS_MODULE,
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+ .release = pppolac_release,
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+ .bind = sock_no_bind,
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+ .connect = pppolac_connect,
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+ .socketpair = sock_no_socketpair,
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+ .accept = sock_no_accept,
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+ .getname = sock_no_getname,
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+ .poll = sock_no_poll,
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+ .ioctl = pppox_ioctl,
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+ .listen = sock_no_listen,
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+ .shutdown = sock_no_shutdown,
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+ .setsockopt = sock_no_setsockopt,
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+ .getsockopt = sock_no_getsockopt,
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+ .sendmsg = sock_no_sendmsg,
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+ .recvmsg = sock_no_recvmsg,
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+ .mmap = sock_no_mmap,
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+};
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+
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+static int pppolac_create(struct net *net, struct socket *sock, int kern)
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+{
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+ struct sock *sk;
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+
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+ sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppolac_proto, kern);
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+ if (!sk)
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+ return -ENOMEM;
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+
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+ sock_init_data(sock, sk);
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+ sock->state = SS_UNCONNECTED;
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+ sock->ops = &pppolac_proto_ops;
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+ sk->sk_protocol = PX_PROTO_OLAC;
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+ sk->sk_state = PPPOX_NONE;
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+ return 0;
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+}
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+
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+/******************************************************************************/
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+
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+static struct pppox_proto pppolac_pppox_proto = {
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+ .create = pppolac_create,
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+ .owner = THIS_MODULE,
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+};
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+
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+static int __init pppolac_init(void)
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+{
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+ int error;
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+
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+ error = proto_register(&pppolac_proto, 0);
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+ if (error)
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+ return error;
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+
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+ error = register_pppox_proto(PX_PROTO_OLAC, &pppolac_pppox_proto);
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+ if (error)
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+ proto_unregister(&pppolac_proto);
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+ else
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+ skb_queue_head_init(&delivery_queue);
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+ return error;
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+}
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+
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+static void __exit pppolac_exit(void)
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+{
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+ unregister_pppox_proto(PX_PROTO_OLAC);
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+ proto_unregister(&pppolac_proto);
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+}
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+
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+module_init(pppolac_init);
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+module_exit(pppolac_exit);
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+
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+MODULE_DESCRIPTION("PPP on L2TP Access Concentrator (PPPoLAC)");
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+MODULE_AUTHOR("Chia-chi Yeh <chiachi@android.com>");
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|
+MODULE_LICENSE("GPL");
|