pespin has submitted this change. ( https://gerrit.osmocom.org/c/libosmocore/+/34113 ) Change subject: socket: Add osmo_sock_init flag to enable SCTP ASCONF features ...................................................................... socket: Add osmo_sock_init flag to enable SCTP ASCONF features The SCTP_ASCONF_SUPPORTED sockopt, which enables ASCONF features for the SCTP associations managed by the SCTP socket, gets its default value from to sysctl "net.sctp.addip_enable", which, at least up to current kernel 6.4.8 is set to "0" (disabled) by default. As a result, ASCONF related features such as setsockopt(SCTP_SET_PEER_PRIMARY_ADDR) fail with -EPERM since ASNCONF extensions where not negotiated during the SCTP init handshake. This commit adds support for setting SCTP_ASCONF_SUPPORTED=1 during socket creation, since that needs to be applied before the first bind()/connect() (before first assoc is created). Furthermore, for ASCONF features to work properly, the assoc also needs to announce/use the AUTH extension, as per RFC5061 section 4.2.7. Otherwise, the peer receiving an SCTP INIT with ExtensionFeatures=ASCONF,ASCONF_ACK but without AUTH, will reject the assoc with an ABORT since it's not complying with spec (this behavior can be tweaked through sysctl "net.sctp.addip_noauth_enable"). The AUTH extension is enabled through sockopt SCTP_AUTH_SUPPORTED, and its default value is that of sysctl "net.sctp.auth_enable", which is also disabled (0) by default. Kernel support for those is relatively new: SCTP_FUTURE_ASSOC added in: 80df2704a375bb4b3c9c5cce9c00052361b16d61 Follows: v5.0-rc4 Precedes: v5.1-rc1 SCTP_ASCONF_SUPPORTED added in: df2c71ffdfae58961981d7cbcccea93688fc4e96 Follows: v5.3-rc5 Precedes: v5.4-rc1 SCTP_AUTH_SUPPORTED added in: 56dd525abd56f7acd7b44a52935726e3ada4916c Follows: v5.3-rc5 Precedes: v5.4-rc1 Related: OS#6076 Change-Id: Iac07031927b66a9d32d2bb2faab817e4c922a359 --- M include/osmocom/core/socket.h M src/core/socket.c 2 files changed, 101 insertions(+), 0 deletions(-) Approvals: pespin: Looks good to me, approved Jenkins Builder: Verified diff --git a/include/osmocom/core/socket.h b/include/osmocom/core/socket.h index 6bac87d..c68bb6f 100644 --- a/include/osmocom/core/socket.h +++ b/include/osmocom/core/socket.h @@ -94,6 +94,8 @@ #define OSMO_SOCK_F_NO_MCAST_ALL (1 << 4) /*! use SO_REUSEADDR on UDP ports (required for multicast) */ #define OSMO_SOCK_F_UDP_REUSEADDR (1 << 5) +/*! use SCTP_AUTH_SUPPORTED + SCTP_ASCONF_SUPPORTED on SCTP socket (required for ASCONF / Peer Primary Address feature) */ +#define OSMO_SOCK_F_SCTP_ASCONF_SUPPORTED (1 << 6) /*! use OSMO_SOCK_F_DSCP(x) to set IP DSCP 'x' for packets transmitted on the socket */ #define OSMO_SOCK_F_DSCP(x) (((x)&0x3f) << 24) diff --git a/src/core/socket.c b/src/core/socket.c index 5a31c8f..02d05e2 100644 --- a/src/core/socket.c +++ b/src/core/socket.c @@ -696,6 +696,36 @@ return 0; } +static int setsockopt_sctp_auth_supported(int fd) +{ +#ifdef SCTP_AUTH_SUPPORTED + struct sctp_assoc_value assoc_val = { + .assoc_id = SCTP_FUTURE_ASSOC, + .assoc_value = 1, + }; + return setsockopt(fd, IPPROTO_SCTP, SCTP_AUTH_SUPPORTED, &assoc_val, sizeof(assoc_val)); +#else +#pragma message "setsockopt(SCTP_AUTH_SUPPORTED) not supported! some SCTP features may not be available!" + LOGP(DLGLOBAL, LOGL_NOTICE, "Built without support for setsockopt(SCTP_AUTH_SUPPORTED), skipping\n"); + return 0; +#endif +} + +static int setsockopt_sctp_asconf_supported(int fd) +{ +#ifdef SCTP_ASCONF_SUPPORTED + struct sctp_assoc_value assoc_val = { + .assoc_id = SCTP_FUTURE_ASSOC, + .assoc_value = 1, + }; + return setsockopt(fd, IPPROTO_SCTP, SCTP_ASCONF_SUPPORTED, &assoc_val, sizeof(assoc_val)); +#else +#pragma message "setsockopt(SCTP_ASCONF_SUPPORTED) not supported! some SCTP features may not be available!" + LOGP(DLGLOBAL, LOGL_NOTICE, "Built without support for setsockopt(SCTP_ASCONF_SUPPORTED), skipping\n"); + return 0; +#endif +} + /*! Initialize a socket (including bind and/or connect) with multiple local or remote addresses. * \param[in] family Address Family like AF_INET, AF_INET6, AF_UNSPEC * \param[in] type Socket type like SOCK_DGRAM, SOCK_STREAM @@ -811,6 +841,29 @@ goto ret_close; } + if (flags & OSMO_SOCK_F_SCTP_ASCONF_SUPPORTED) { + /* RFC 5061 4.2.7: ASCONF also requires AUTH feature. */ + rc = setsockopt_sctp_auth_supported(sfd); + if (rc < 0) { + int err = errno; + multiaddr_snprintf(strbuf, sizeof(strbuf), local_hosts, local_hosts_cnt); + LOGP(DLGLOBAL, LOGL_ERROR, + "cannot setsockopt(SCTP_AUTH_SUPPORTED) socket: %s:%u: %s\n", + strbuf, local_port, strerror(err)); + goto ret_close; + } + + rc = setsockopt_sctp_asconf_supported(sfd); + if (rc < 0) { + int err = errno; + multiaddr_snprintf(strbuf, sizeof(strbuf), local_hosts, local_hosts_cnt); + LOGP(DLGLOBAL, LOGL_ERROR, + "cannot setsockopt(SCTP_ASCONF_SUPPORTED) socket: %s:%u: %s\n", + strbuf, local_port, strerror(err)); + goto ret_close; + } + } + /* Build array of addresses taking first entry for each host. TODO: Ideally we should use backtracking storing last used indexes and trying next combination if connect() fails .*/ -- To view, visit https://gerrit.osmocom.org/c/libosmocore/+/34113 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: libosmocore Gerrit-Branch: master Gerrit-Change-Id: Iac07031927b66a9d32d2bb2faab817e4c922a359 Gerrit-Change-Number: 34113 Gerrit-PatchSet: 3 Gerrit-Owner: pespin &lt;pespin(a)sysmocom.de&gt; Gerrit-Reviewer: Jenkins Builder Gerrit-Reviewer: laforge &lt;laforge(a)osmocom.org&gt; Gerrit-Reviewer: osmith &lt;osmith(a)sysmocom.de&gt; Gerrit-Reviewer: pespin &lt;pespin(a)sysmocom.de&gt; Gerrit-MessageType: merged