kernel/include/net/netns/sctp.h, branch linux-6.18.y

sctp: Convert cookie authentication to use HMAC-SHA256

2025-08-20T02:36:26Z

Convert SCTP cookies to use HMAC-SHA256, instead of the previous choice of the legacy algorithms HMAC-MD5 and HMAC-SHA1. Simplify and optimize the code by using the HMAC-SHA256 library instead of crypto_shash, and by preparing the HMAC key when it is generated instead of per-operation. This doesn't break compatibility, since the cookie format is an implementation detail, not part of the SCTP protocol itself. Note that the cookie size doesn't change either. The HMAC field was already 32 bytes, even though previously at most 20 bytes were actually compared. 32 bytes exactly fits an untruncated HMAC-SHA256 value. So, although we could safely truncate the MAC to something slightly shorter, for now just keep the cookie size the same. I also considered SipHash, but that would generate only 8-byte MACs. An 8-byte MAC *might* suffice here. However, there's quite a lot of information in the SCTP cookies: more than in TCP SYN cookies. So absent an analysis that occasional forgeries of all that information is okay in SCTP, I errored on the side of caution. Remove HMAC-MD5 and HMAC-SHA1 as options, since the new HMAC-SHA256 option is just better. It's faster as well as more secure. For example, benchmarking on x86_64, cookie authentication is now nearly 3x as fast as the previous default choice and implementation of HMAC-MD5. Also just make the kernel always support cookie authentication if SCTP is supported at all, rather than making it optional in the build. (It was sort of optional before, but it didn't really work properly. E.g., a kernel with CONFIG_SCTP_COOKIE_HMAC_MD5=n still supported HMAC-MD5 cookie authentication if CONFIG_CRYPTO_HMAC and CONFIG_CRYPTO_MD5 happened to be enabled in the kconfig for other reasons.) Acked-by: Xin Long Signed-off-by: Eric Biggers Link: https://patch.msgid.link/20250818205426.30222-5-ebiggers@kernel.org Signed-off-by: Jakub Kicinski

net: Correct spelling in headers

2024-08-26T16:37:23Z

Correct spelling in Networking headers. As reported by codespell. Signed-off-by: Simon Horman Link: https://patch.msgid.link/20240822-net-spell-v1-12-3a98971ce2d2@kernel.org Signed-off-by: Jakub Kicinski

sctp: add dif and sdif check in asoc and ep lookup

2022-11-18T11:42:54Z

This patch at first adds a pernet global l3mdev_accept to decide if it accepts the packets from a l3mdev when a SCTP socket doesn't bind to any interface. It's set to 1 to avoid any possible incompatible issue, and in next patch, a sysctl will be introduced to allow to change it. Then similar to inet/udp_sk_bound_dev_eq(), sctp_sk_bound_dev_eq() is added to check either dif or sdif is equal to sk_bound_dev_if, and to check sid is 0 or l3mdev_accept is 1 if sk_bound_dev_if is not set. This function is used to match a association or a endpoint, namely called by sctp_addrs_lookup_transport() and sctp_endpoint_is_match(). All functions that needs updating are: sctp_rcv(): asoc: __sctp_rcv_lookup() __sctp_lookup_association() -> sctp_addrs_lookup_transport() __sctp_rcv_lookup_harder() __sctp_rcv_init_lookup() __sctp_lookup_association() -> sctp_addrs_lookup_transport() __sctp_rcv_walk_lookup() __sctp_rcv_asconf_lookup() __sctp_lookup_association() -> sctp_addrs_lookup_transport() ep: __sctp_rcv_lookup_endpoint() -> sctp_endpoint_is_match() sctp_connect(): sctp_endpoint_is_peeled_off() __sctp_lookup_association() sctp_has_association() sctp_lookup_association() __sctp_lookup_association() -> sctp_addrs_lookup_transport() sctp_diag_dump_one(): sctp_transport_lookup_process() -> sctp_addrs_lookup_transport() Signed-off-by: Xin Long Signed-off-by: David S. Miller

net: add missing includes and forward declarations under net/

2022-07-22T11:53:22Z

This patch adds missing includes to headers under include/net. All these problems are currently masked by the existing users including the missing dependency before the broken header. Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller

sctp: add probe_interval in sysctl and sock/asoc/transport

2021-06-22T18:28:51Z

PLPMTUD can be enabled by doing 'sysctl -w net.sctp.probe_interval=n'. 'n' is the interval for PLPMTUD probe timer in milliseconds, and it can't be less than 5000 if it's not 0. All asoc/transport's PLPMTUD in a new socket will be enabled by default. Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller

sctp: add encap_port for netns sock asoc and transport

2020-10-30T22:24:06Z

encap_port is added as per netns/sock/assoc/transport, and the latter one's encap_port inherits the former one's by default. The transport's encap_port value would mostly decide if one packet should go out with udp encapsulated or not. This patch also allows users to set netns' encap_port by sysctl. v1->v2: - Change to define encap_port as __be16 for sctp_sock, asoc and transport. v2->v3: - No change. v3->v4: - Add 'encap_port' entry in ip-sysctl.rst. v4->v5: - Improve the description of encap_port in ip-sysctl.rst. Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: Jakub Kicinski

sctp: create udp6 sock and set its encap_rcv

2020-10-30T22:23:56Z

This patch is to add the udp6 sock part in sctp_udp_sock_start/stop(). udp_conf.use_udp6_rx_checksums is set to true, as: "The SCTP checksum MUST be computed for IPv4 and IPv6, and the UDP checksum SHOULD be computed for IPv4 and IPv6" says in rfc6951#section-5.3. v1->v2: - Add pr_err() when fails to create udp v6 sock. - Add #if IS_ENABLED(CONFIG_IPV6) not to create v6 sock when ipv6 is disabled. Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: Jakub Kicinski

sctp: create udp4 sock and add its encap_rcv

2020-10-30T22:23:52Z

This patch is to add the functions to create/release udp4 sock, and set the sock's encap_rcv to process the incoming udp encap sctp packets. In sctp_udp_rcv(), as we can see, all we need to do is fix the transport header for sctp_rcv(), then it would implement the part of rfc6951#section-5.4: "When an encapsulated packet is received, the UDP header is removed. Then, the generic lookup is performed, as done by an SCTP stack whenever a packet is received, to find the association for the received SCTP packet" Note that these functions will be called in the last patch of this patchset when enabling this feature. v1->v2: - Add pr_err() when fails to create udp v4 sock. v2->v3: - Add 'select NET_UDP_TUNNEL' in sctp Kconfig. v3->v4: - No change. v4->v5: - Change to set udp_port to 0 by default. Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: Jakub Kicinski

sctp: add support for Primary Path Switchover

2019-11-08T22:18:32Z

This is a new feature defined in section 5 of rfc7829: "Primary Path Switchover". By introducing a new tunable parameter: Primary.Switchover.Max.Retrans (PSMR) The primary path will be changed to another active path when the path error counter on the old primary path exceeds PSMR, so that "the SCTP sender is allowed to continue data transmission on a new working path even when the old primary destination address becomes active again". This patch is to add this tunable parameter, 'ps_retrans' per netns, sock, asoc and transport. It also allows a user to change ps_retrans per netns by sysctl, and ps_retrans per sock/asoc/transport will be initialized with it. The check will be done in sctp_do_8_2_transport_strike() when this feature is enabled. Note this feature is disabled by initializing 'ps_retrans' per netns as 0xffff by default, and its value can't be less than 'pf_retrans' when changing by sysctl. v3->v4: - add define SCTP_PS_RETRANS_MAX 0xffff, and use it on extra2 of sysctl 'ps_retrans'. - add a new entry for ps_retrans on ip-sysctl.txt. Signed-off-by: Xin Long Acked-by: Neil Horman Signed-off-by: David S. Miller

sctp: add pf_expose per netns and sock and asoc

2019-11-08T22:18:32Z

As said in rfc7829, section 3, point 12: The SCTP stack SHOULD expose the PF state of its destination addresses to the ULP as well as provide the means to notify the ULP of state transitions of its destination addresses from active to PF, and vice versa. However, it is recommended that an SCTP stack implementing SCTP-PF also allows for the ULP to be kept ignorant of the PF state of its destinations and the associated state transitions, thus allowing for retention of the simpler state transition model of [RFC4960] in the ULP. Not only does it allow to expose the PF state to ULP, but also allow to ignore sctp-pf to ULP. So this patch is to add pf_expose per netns, sock and asoc. And in sctp_assoc_control_transport(), ulp_notify will be set to false if asoc->expose is not 'enabled' in next patch. It also allows a user to change pf_expose per netns by sysctl, and pf_expose per sock and asoc will be initialized with it. Note that pf_expose also works for SCTP_GET_PEER_ADDR_INFO sockopt, to not allow a user to query the state of a sctp-pf peer address when pf_expose is 'disabled', as said in section 7.3. v1->v2: - Fix a build warning noticed by Nathan Chancellor. v2->v3: - set pf_expose to UNUSED by default to keep compatible with old applications. v3->v4: - add a new entry for pf_expose on ip-sysctl.txt, as Marcelo suggested. - change this patch to 1/5, and move sctp_assoc_control_transport change into 2/5, as Marcelo suggested. - use SCTP_PF_EXPOSE_UNSET instead of SCTP_PF_EXPOSE_UNUSED, and set SCTP_PF_EXPOSE_UNSET to 0 in enum, as Marcelo suggested. Signed-off-by: Xin Long Acked-by: Neil Horman Signed-off-by: David S. Miller