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Add hooks to parse and format the MP_CAPABLE option. This option is handled according to MPTCP version 0 (RFC6824). MPTCP version 1 MP_CAPABLE (RFC6824bis/RFC8684) will be added later in coordination with related code changes. Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Co-developed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Florian Westphal <fw@strlen.de> Co-developed-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com> Signed-off-by: Christoph Paasch <cpaasch@apple.com> Signed-off-by: David S. Miller <davem@davemloft.net>
98 lines
2.4 KiB
C
98 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Multipath TCP
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*
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* Copyright (c) 2017 - 2019, Intel Corporation.
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*/
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#include <linux/kernel.h>
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#include <net/tcp.h>
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#include <net/mptcp.h>
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#include "protocol.h"
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void mptcp_parse_option(const unsigned char *ptr, int opsize,
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struct tcp_options_received *opt_rx)
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{
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struct mptcp_options_received *mp_opt = &opt_rx->mptcp;
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u8 subtype = *ptr >> 4;
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u8 version;
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u8 flags;
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switch (subtype) {
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case MPTCPOPT_MP_CAPABLE:
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if (opsize != TCPOLEN_MPTCP_MPC_SYN &&
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opsize != TCPOLEN_MPTCP_MPC_ACK)
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break;
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version = *ptr++ & MPTCP_VERSION_MASK;
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if (version != MPTCP_SUPPORTED_VERSION)
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break;
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flags = *ptr++;
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if (!((flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA1) ||
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(flags & MPTCP_CAP_EXTENSIBILITY))
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break;
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/* RFC 6824, Section 3.1:
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* "For the Checksum Required bit (labeled "A"), if either
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* host requires the use of checksums, checksums MUST be used.
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* In other words, the only way for checksums not to be used
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* is if both hosts in their SYNs set A=0."
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*
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* Section 3.3.0:
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* "If a checksum is not present when its use has been
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* negotiated, the receiver MUST close the subflow with a RST as
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* it is considered broken."
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*
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* We don't implement DSS checksum - fall back to TCP.
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*/
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if (flags & MPTCP_CAP_CHECKSUM_REQD)
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break;
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mp_opt->mp_capable = 1;
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mp_opt->sndr_key = get_unaligned_be64(ptr);
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ptr += 8;
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if (opsize == TCPOLEN_MPTCP_MPC_ACK) {
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mp_opt->rcvr_key = get_unaligned_be64(ptr);
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ptr += 8;
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pr_debug("MP_CAPABLE sndr=%llu, rcvr=%llu",
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mp_opt->sndr_key, mp_opt->rcvr_key);
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} else {
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pr_debug("MP_CAPABLE sndr=%llu", mp_opt->sndr_key);
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}
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break;
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case MPTCPOPT_DSS:
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pr_debug("DSS");
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mp_opt->dss = 1;
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break;
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default:
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break;
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}
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}
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void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
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{
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if ((OPTION_MPTCP_MPC_SYN |
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OPTION_MPTCP_MPC_ACK) & opts->suboptions) {
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u8 len;
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if (OPTION_MPTCP_MPC_SYN & opts->suboptions)
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len = TCPOLEN_MPTCP_MPC_SYN;
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else
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len = TCPOLEN_MPTCP_MPC_ACK;
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*ptr++ = htonl((TCPOPT_MPTCP << 24) | (len << 16) |
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(MPTCPOPT_MP_CAPABLE << 12) |
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(MPTCP_SUPPORTED_VERSION << 8) |
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MPTCP_CAP_HMAC_SHA1);
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put_unaligned_be64(opts->sndr_key, ptr);
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ptr += 2;
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if (OPTION_MPTCP_MPC_ACK & opts->suboptions) {
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put_unaligned_be64(opts->rcvr_key, ptr);
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ptr += 2;
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}
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}
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}
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