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-rw-r--r--include/uapi/linux/l2tp.h2
-rw-r--r--net/l2tp/l2tp_core.c1
-rw-r--r--net/l2tp/l2tp_core.h20
-rw-r--r--net/l2tp/l2tp_debugfs.c3
-rw-r--r--net/l2tp/l2tp_eth.c25
-rw-r--r--net/l2tp/l2tp_netlink.c9
-rw-r--r--net/l2tp/l2tp_ppp.c74
7 files changed, 47 insertions, 87 deletions
diff --git a/include/uapi/linux/l2tp.h b/include/uapi/linux/l2tp.h
index 8bb8c7cfabe5..61158f5a1a5b 100644
--- a/include/uapi/linux/l2tp.h
+++ b/include/uapi/linux/l2tp.h
@@ -119,7 +119,7 @@ enum {
L2TP_ATTR_IP_DADDR, /* u32 */
L2TP_ATTR_UDP_SPORT, /* u16 */
L2TP_ATTR_UDP_DPORT, /* u16 */
- L2TP_ATTR_MTU, /* u16 */
+ L2TP_ATTR_MTU, /* u16 (not used) */
L2TP_ATTR_MRU, /* u16 (not used) */
L2TP_ATTR_STATS, /* nested */
L2TP_ATTR_IP6_SADDR, /* struct in6_addr */
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index c61a467fd9b8..ac6a00bcec71 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1674,7 +1674,6 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn
if (cfg) {
session->pwtype = cfg->pw_type;
session->debug = cfg->debug;
- session->mtu = cfg->mtu;
session->send_seq = cfg->send_seq;
session->recv_seq = cfg->recv_seq;
session->lns_mode = cfg->lns_mode;
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index fa5ae9432d38..5804065dfbfb 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -12,6 +12,9 @@
#ifndef _L2TP_CORE_H_
#define _L2TP_CORE_H_
+#include <net/dst.h>
+#include <net/sock.h>
+
/* Just some random numbers */
#define L2TP_TUNNEL_MAGIC 0x42114DDA
#define L2TP_SESSION_MAGIC 0x0C04EB7D
@@ -61,7 +64,6 @@ struct l2tp_session_cfg {
int peer_cookie_len; /* 0, 4 or 8 bytes */
int reorder_timeout; /* configured reorder timeout
* (in jiffies) */
- int mtu;
char *ifname;
};
@@ -105,7 +107,6 @@ struct l2tp_session {
int reorder_timeout; /* configured reorder timeout
* (in jiffies) */
int reorder_skip; /* set if skip to next nr */
- int mtu;
enum l2tp_pwtype pwtype;
struct l2tp_stats stats;
struct hlist_node global_hlist; /* Global hash list node */
@@ -268,6 +269,21 @@ static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
}
}
+static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel)
+{
+ struct dst_entry *dst;
+ u32 mtu;
+
+ dst = sk_dst_get(tunnel->sock);
+ if (!dst)
+ return 0;
+
+ mtu = dst_mtu(dst);
+ dst_release(dst);
+
+ return mtu;
+}
+
#define l2tp_printk(ptr, type, func, fmt, ...) \
do { \
if (((ptr)->debug) & (type)) \
diff --git a/net/l2tp/l2tp_debugfs.c b/net/l2tp/l2tp_debugfs.c
index aee271741f5b..9821a1458555 100644
--- a/net/l2tp/l2tp_debugfs.c
+++ b/net/l2tp/l2tp_debugfs.c
@@ -191,8 +191,7 @@ static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
if (session->send_seq || session->recv_seq)
seq_printf(m, " nr %hu, ns %hu\n", session->nr, session->ns);
seq_printf(m, " refcnt %d\n", refcount_read(&session->ref_count));
- seq_printf(m, " config %d/0/%c/%c/-/%s %08x %u\n",
- session->mtu,
+ seq_printf(m, " config 0/0/%c/%c/-/%s %08x %u\n",
session->recv_seq ? 'R' : '-',
session->send_seq ? 'S' : '-',
session->lns_mode ? "LNS" : "LAC",
diff --git a/net/l2tp/l2tp_eth.c b/net/l2tp/l2tp_eth.c
index 5c366ecfa1cb..3728986ec885 100644
--- a/net/l2tp/l2tp_eth.c
+++ b/net/l2tp/l2tp_eth.c
@@ -226,22 +226,19 @@ static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
struct net_device *dev)
{
unsigned int overhead = 0;
- struct dst_entry *dst;
u32 l3_overhead = 0;
+ u32 mtu;
/* if the encap is UDP, account for UDP header size */
if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
overhead += sizeof(struct udphdr);
dev->needed_headroom += sizeof(struct udphdr);
}
- if (session->mtu != 0) {
- dev->mtu = session->mtu;
- dev->needed_headroom += session->hdr_len;
- return;
- }
+
lock_sock(tunnel->sock);
l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
release_sock(tunnel->sock);
+
if (l3_overhead == 0) {
/* L3 Overhead couldn't be identified, this could be
* because tunnel->sock was NULL or the socket's
@@ -255,18 +252,12 @@ static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
*/
overhead += session->hdr_len + ETH_HLEN + l3_overhead;
- /* If PMTU discovery was enabled, use discovered MTU on L2TP device */
- dst = sk_dst_get(tunnel->sock);
- if (dst) {
- /* dst_mtu will use PMTU if found, else fallback to intf MTU */
- u32 pmtu = dst_mtu(dst);
+ mtu = l2tp_tunnel_dst_mtu(tunnel) - overhead;
+ if (mtu < dev->min_mtu || mtu > dev->max_mtu)
+ dev->mtu = ETH_DATA_LEN - overhead;
+ else
+ dev->mtu = mtu;
- if (pmtu != 0)
- dev->mtu = pmtu;
- dst_release(dst);
- }
- session->mtu = dev->mtu - overhead;
- dev->mtu = session->mtu;
dev->needed_headroom += session->hdr_len;
}
diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index a7c409215336..2e1e92651545 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -608,9 +608,6 @@ static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *inf
if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
- if (info->attrs[L2TP_ATTR_MTU])
- cfg.mtu = nla_get_u16(info->attrs[L2TP_ATTR_MTU]);
-
#ifdef CONFIG_MODULES
if (l2tp_nl_cmd_ops[cfg.pw_type] == NULL) {
genl_unlock();
@@ -698,9 +695,6 @@ static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *inf
if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
session->reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);
- if (info->attrs[L2TP_ATTR_MTU])
- session->mtu = nla_get_u16(info->attrs[L2TP_ATTR_MTU]);
-
ret = l2tp_session_notify(&l2tp_nl_family, info,
session, L2TP_CMD_SESSION_MODIFY);
@@ -730,8 +724,7 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq, int fl
nla_put_u32(skb, L2TP_ATTR_PEER_SESSION_ID,
session->peer_session_id) ||
nla_put_u32(skb, L2TP_ATTR_DEBUG, session->debug) ||
- nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype) ||
- nla_put_u16(skb, L2TP_ATTR_MTU, session->mtu))
+ nla_put_u16(skb, L2TP_ATTR_PW_TYPE, session->pwtype))
goto nla_put_failure;
if ((session->ifname[0] &&
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 44cac66284a5..b403728e2757 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -93,7 +93,6 @@
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
-#include <net/dst.h>
#include <net/ip.h>
#include <net/udp.h>
#include <net/xfrm.h>
@@ -554,7 +553,6 @@ static void pppol2tp_show(struct seq_file *m, void *arg)
static void pppol2tp_session_init(struct l2tp_session *session)
{
struct pppol2tp_session *ps;
- struct dst_entry *dst;
session->recv_skb = pppol2tp_recv;
#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
@@ -564,17 +562,6 @@ static void pppol2tp_session_init(struct l2tp_session *session)
ps = l2tp_session_priv(session);
mutex_init(&ps->sk_lock);
ps->owner = current->pid;
-
- /* If PMTU discovery was enabled, use the MTU that was discovered */
- dst = sk_dst_get(session->tunnel->sock);
- if (dst) {
- u32 pmtu = dst_mtu(dst);
-
- if (pmtu)
- session->mtu = pmtu - PPPOL2TP_HEADER_OVERHEAD;
-
- dst_release(dst);
- }
}
struct l2tp_connect_info {
@@ -661,6 +648,22 @@ static int pppol2tp_sockaddr_get_info(const void *sa, int sa_len,
return 0;
}
+/* Rough estimation of the maximum payload size a tunnel can transmit without
+ * fragmenting at the lower IP layer. Assumes L2TPv2 with sequence
+ * numbers and no IP option. Not quite accurate, but the result is mostly
+ * unused anyway.
+ */
+static int pppol2tp_tunnel_mtu(const struct l2tp_tunnel *tunnel)
+{
+ int mtu;
+
+ mtu = l2tp_tunnel_dst_mtu(tunnel);
+ if (mtu <= PPPOL2TP_HEADER_OVERHEAD)
+ return 1500 - PPPOL2TP_HEADER_OVERHEAD;
+
+ return mtu - PPPOL2TP_HEADER_OVERHEAD;
+}
+
/* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
*/
static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
@@ -778,8 +781,6 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
goto end;
}
} else {
- /* Default MTU must allow space for UDP/L2TP/PPP headers */
- cfg.mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD;
cfg.pw_type = L2TP_PWTYPE_PPP;
session = l2tp_session_create(sizeof(struct pppol2tp_session),
@@ -824,7 +825,7 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
po->chan.private = sk;
po->chan.ops = &pppol2tp_chan_ops;
- po->chan.mtu = session->mtu;
+ po->chan.mtu = pppol2tp_tunnel_mtu(tunnel);
error = ppp_register_net_channel(sock_net(sk), &po->chan);
if (error) {
@@ -880,10 +881,6 @@ static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
goto err;
}
- /* Default MTU values. */
- if (cfg->mtu == 0)
- cfg->mtu = 1500 - PPPOL2TP_HEADER_OVERHEAD;
-
/* Allocate and initialize a new session context. */
session = l2tp_session_create(sizeof(struct pppol2tp_session),
tunnel, session_id,
@@ -1047,7 +1044,6 @@ static void pppol2tp_copy_stats(struct pppol2tp_ioc_stats *dest,
static int pppol2tp_session_ioctl(struct l2tp_session *session,
unsigned int cmd, unsigned long arg)
{
- struct ifreq ifr;
int err = 0;
struct sock *sk;
int val = (int) arg;
@@ -1063,39 +1059,6 @@ static int pppol2tp_session_ioctl(struct l2tp_session *session,
return -EBADR;
switch (cmd) {
- case SIOCGIFMTU:
- err = -ENXIO;
- if (!(sk->sk_state & PPPOX_CONNECTED))
- break;
-
- err = -EFAULT;
- if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
- break;
- ifr.ifr_mtu = session->mtu;
- if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
- break;
-
- l2tp_info(session, L2TP_MSG_CONTROL, "%s: get mtu=%d\n",
- session->name, session->mtu);
- err = 0;
- break;
-
- case SIOCSIFMTU:
- err = -ENXIO;
- if (!(sk->sk_state & PPPOX_CONNECTED))
- break;
-
- err = -EFAULT;
- if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
- break;
-
- session->mtu = ifr.ifr_mtu;
-
- l2tp_info(session, L2TP_MSG_CONTROL, "%s: set mtu=%d\n",
- session->name, session->mtu);
- err = 0;
- break;
-
case PPPIOCGMRU:
case PPPIOCGFLAGS:
err = -EFAULT;
@@ -1692,8 +1655,7 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
tunnel->peer_tunnel_id,
session->peer_session_id,
state, user_data_ok);
- seq_printf(m, " %d/0/%c/%c/%s %08x %u\n",
- session->mtu,
+ seq_printf(m, " 0/0/%c/%c/%s %08x %u\n",
session->recv_seq ? 'R' : '-',
session->send_seq ? 'S' : '-',
session->lns_mode ? "LNS" : "LAC",
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-18 18:25:02 +0000