linux-stable/include
Florian Westphal c11c5906bc mptcp: add MPTCP_SUBFLOW_ADDRS getsockopt support
This retrieves the address pairs of all subflows currently
active for a given mptcp connection.

It re-uses the same meta-header as for MPTCP_TCPINFO.

A new structure is provided to hold the subflow
address data:

struct mptcp_subflow_addrs {
	union {
		__kernel_sa_family_t sa_family;
		struct sockaddr sa_local;
		struct sockaddr_in sin_local;
		struct sockaddr_in6 sin6_local;
		struct sockaddr_storage ss_local;
	};
	union {
		struct sockaddr sa_remote;
		struct sockaddr_in sin_remote;
		struct sockaddr_in6 sin6_remote;
		struct sockaddr_storage ss_remote;
	};
};

Usage of the new getsockopt is very similar to
MPTCP_TCPINFO one.

Userspace allocates a
'struct mptcp_subflow_data', followed by one or
more 'struct mptcp_subflow_addrs', then inits the
mptcp_subflow_data structure as follows:

struct mptcp_subflow_addrs *sf_addr;
struct mptcp_subflow_data *addr;
socklen_t olen = sizeof(*addr) + (8 * sizeof(*sf_addr));

addr = malloc(olen);
addr->size_subflow_data = sizeof(*addr);
addr->num_subflows = 0;
addr->size_kernel = 0;
addr->size_user = sizeof(struct mptcp_subflow_addrs);

sf_addr = (struct mptcp_subflow_addrs *)(addr + 1);

and then retrieves the endpoint addresses via:
ret = getsockopt(fd, SOL_MPTCP, MPTCP_SUBFLOW_ADDRS,
		 addr, &olen);

If the call succeeds, kernel will have added up to 8
endpoint addresses after the 'mptcp_subflow_data' header.

Userspace needs to re-check 'olen' value to detect how
many bytes have been filled in by the kernel.

Userspace can check addr->num_subflows to discover when
there were more subflows that available data space.

Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-18 14:20:01 +01:00
..
acpi Merge branches 'pm-cpufreq', 'pm-sleep' and 'pm-em' 2021-09-10 20:26:08 +02:00
asm-generic hyperv-fixes for 5.15-rc2 2021-09-15 17:18:56 -07:00
clocksource
crypto
drm
dt-bindings linux-watchdog 5.15-rc1 tag 2021-09-07 13:52:46 -07:00
keys
kunit
kvm
linux mptcp: add MPTCP_INFO getsockopt 2021-09-18 14:20:01 +01:00
math-emu
media
memory
misc
net mptcp: add new mptcp_fill_diag helper 2021-09-18 14:20:00 +01:00
pcmcia
ras
rdma
scsi
soc
sound
target
trace Merge branch 'akpm' (patches from Andrew) 2021-09-08 12:55:35 -07:00
uapi mptcp: add MPTCP_SUBFLOW_ADDRS getsockopt support 2021-09-18 14:20:01 +01:00
vdso
video
xen