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-rw-r--r--net/ipv4/tcp_input.c5
-rw-r--r--net/ipv4/tcp_output.c13
-rw-r--r--net/mptcp/Makefile2
-rw-r--r--net/mptcp/options.c97
-rw-r--r--net/mptcp/protocol.h29
5 files changed, 145 insertions, 1 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 358365598216..3458ee13e6f0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -79,6 +79,7 @@
#include <trace/events/tcp.h>
#include <linux/jump_label_ratelimit.h>
#include <net/busy_poll.h>
+#include <net/mptcp.h>
int sysctl_tcp_max_orphans __read_mostly = NR_FILE;
@@ -3924,6 +3925,10 @@ void tcp_parse_options(const struct net *net,
*/
break;
#endif
+ case TCPOPT_MPTCP:
+ mptcp_parse_option(ptr, opsize, opt_rx);
+ break;
+
case TCPOPT_FASTOPEN:
tcp_parse_fastopen_option(
opsize - TCPOLEN_FASTOPEN_BASE,
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 786978cb2db7..0f0984f39f67 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -38,6 +38,7 @@
#define pr_fmt(fmt) "TCP: " fmt
#include <net/tcp.h>
+#include <net/mptcp.h>
#include <linux/compiler.h>
#include <linux/gfp.h>
@@ -414,6 +415,7 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp)
#define OPTION_WSCALE (1 << 3)
#define OPTION_FAST_OPEN_COOKIE (1 << 8)
#define OPTION_SMC (1 << 9)
+#define OPTION_MPTCP (1 << 10)
static void smc_options_write(__be32 *ptr, u16 *options)
{
@@ -439,8 +441,17 @@ struct tcp_out_options {
__u8 *hash_location; /* temporary pointer, overloaded */
__u32 tsval, tsecr; /* need to include OPTION_TS */
struct tcp_fastopen_cookie *fastopen_cookie; /* Fast open cookie */
+ struct mptcp_out_options mptcp;
};
+static void mptcp_options_write(__be32 *ptr, struct tcp_out_options *opts)
+{
+#if IS_ENABLED(CONFIG_MPTCP)
+ if (unlikely(OPTION_MPTCP & opts->options))
+ mptcp_write_options(ptr, &opts->mptcp);
+#endif
+}
+
/* Write previously computed TCP options to the packet.
*
* Beware: Something in the Internet is very sensitive to the ordering of
@@ -549,6 +560,8 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
}
smc_options_write(ptr, &options);
+
+ mptcp_options_write(ptr, opts);
}
static void smc_set_option(const struct tcp_sock *tp,
diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
index 659129d1fcbf..27a846263f08 100644
--- a/net/mptcp/Makefile
+++ b/net/mptcp/Makefile
@@ -1,4 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_MPTCP) += mptcp.o
-mptcp-y := protocol.o
+mptcp-y := protocol.o options.o
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
new file mode 100644
index 000000000000..b7a31c0e5283
--- /dev/null
+++ b/net/mptcp/options.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#include <linux/kernel.h>
+#include <net/tcp.h>
+#include <net/mptcp.h>
+#include "protocol.h"
+
+void mptcp_parse_option(const unsigned char *ptr, int opsize,
+ struct tcp_options_received *opt_rx)
+{
+ struct mptcp_options_received *mp_opt = &opt_rx->mptcp;
+ u8 subtype = *ptr >> 4;
+ u8 version;
+ u8 flags;
+
+ switch (subtype) {
+ case MPTCPOPT_MP_CAPABLE:
+ if (opsize != TCPOLEN_MPTCP_MPC_SYN &&
+ opsize != TCPOLEN_MPTCP_MPC_ACK)
+ break;
+
+ version = *ptr++ & MPTCP_VERSION_MASK;
+ if (version != MPTCP_SUPPORTED_VERSION)
+ break;
+
+ flags = *ptr++;
+ if (!((flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA1) ||
+ (flags & MPTCP_CAP_EXTENSIBILITY))
+ break;
+
+ /* RFC 6824, Section 3.1:
+ * "For the Checksum Required bit (labeled "A"), if either
+ * host requires the use of checksums, checksums MUST be used.
+ * In other words, the only way for checksums not to be used
+ * is if both hosts in their SYNs set A=0."
+ *
+ * Section 3.3.0:
+ * "If a checksum is not present when its use has been
+ * negotiated, the receiver MUST close the subflow with a RST as
+ * it is considered broken."
+ *
+ * We don't implement DSS checksum - fall back to TCP.
+ */
+ if (flags & MPTCP_CAP_CHECKSUM_REQD)
+ break;
+
+ mp_opt->mp_capable = 1;
+ mp_opt->sndr_key = get_unaligned_be64(ptr);
+ ptr += 8;
+
+ if (opsize == TCPOLEN_MPTCP_MPC_ACK) {
+ mp_opt->rcvr_key = get_unaligned_be64(ptr);
+ ptr += 8;
+ pr_debug("MP_CAPABLE sndr=%llu, rcvr=%llu",
+ mp_opt->sndr_key, mp_opt->rcvr_key);
+ } else {
+ pr_debug("MP_CAPABLE sndr=%llu", mp_opt->sndr_key);
+ }
+ break;
+
+ case MPTCPOPT_DSS:
+ pr_debug("DSS");
+ mp_opt->dss = 1;
+ break;
+
+ default:
+ break;
+ }
+}
+
+void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
+{
+ if ((OPTION_MPTCP_MPC_SYN |
+ OPTION_MPTCP_MPC_ACK) & opts->suboptions) {
+ u8 len;
+
+ if (OPTION_MPTCP_MPC_SYN & opts->suboptions)
+ len = TCPOLEN_MPTCP_MPC_SYN;
+ else
+ len = TCPOLEN_MPTCP_MPC_ACK;
+
+ *ptr++ = htonl((TCPOPT_MPTCP << 24) | (len << 16) |
+ (MPTCPOPT_MP_CAPABLE << 12) |
+ (MPTCP_SUPPORTED_VERSION << 8) |
+ MPTCP_CAP_HMAC_SHA1);
+ put_unaligned_be64(opts->sndr_key, ptr);
+ ptr += 2;
+ if (OPTION_MPTCP_MPC_ACK & opts->suboptions) {
+ put_unaligned_be64(opts->rcvr_key, ptr);
+ ptr += 2;
+ }
+ }
+}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index ee04a01bffd3..c59cf8b220b0 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -7,6 +7,35 @@
#ifndef __MPTCP_PROTOCOL_H
#define __MPTCP_PROTOCOL_H
+#define MPTCP_SUPPORTED_VERSION 0
+
+/* MPTCP option bits */
+#define OPTION_MPTCP_MPC_SYN BIT(0)
+#define OPTION_MPTCP_MPC_SYNACK BIT(1)
+#define OPTION_MPTCP_MPC_ACK BIT(2)
+
+/* MPTCP option subtypes */
+#define MPTCPOPT_MP_CAPABLE 0
+#define MPTCPOPT_MP_JOIN 1
+#define MPTCPOPT_DSS 2
+#define MPTCPOPT_ADD_ADDR 3
+#define MPTCPOPT_RM_ADDR 4
+#define MPTCPOPT_MP_PRIO 5
+#define MPTCPOPT_MP_FAIL 6
+#define MPTCPOPT_MP_FASTCLOSE 7
+
+/* MPTCP suboption lengths */
+#define TCPOLEN_MPTCP_MPC_SYN 12
+#define TCPOLEN_MPTCP_MPC_SYNACK 12
+#define TCPOLEN_MPTCP_MPC_ACK 20
+
+/* MPTCP MP_CAPABLE flags */
+#define MPTCP_VERSION_MASK (0x0F)
+#define MPTCP_CAP_CHECKSUM_REQD BIT(7)
+#define MPTCP_CAP_EXTENSIBILITY BIT(6)
+#define MPTCP_CAP_HMAC_SHA1 BIT(0)
+#define MPTCP_CAP_FLAG_MASK (0x3F)
+
/* MPTCP connection sock */
struct mptcp_sock {
/* inet_connection_sock must be the first member */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.