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 .*/
--
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Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: Iac07031927b66a9d32d2bb2faab817e4c922a359
Gerrit-Change-Number: 34113
Gerrit-PatchSet: 3
Gerrit-Owner: pespin <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: osmith <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>
Gerrit-MessageType: merged
