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Date: Fri, 17 Sep 2021 16:33:21 -0700
From: Mat Martineau <mathew.j.martineau@...ux.intel.com>
To: netdev@...r.kernel.org
Cc: Florian Westphal <fw@...len.de>, davem@...emloft.net,
kuba@...nel.org, matthieu.baerts@...sares.net,
mptcp@...ts.linux.dev,
Mat Martineau <mathew.j.martineau@...ux.intel.com>
Subject: [PATCH net-next 4/5] mptcp: add MPTCP_SUBFLOW_ADDRS getsockopt support
From: Florian Westphal <fw@...len.de>
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@...sares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@...sares.net>
Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@...ux.intel.com>
---
include/uapi/linux/mptcp.h | 24 ++++++++++
net/mptcp/sockopt.c | 91 ++++++++++++++++++++++++++++++++++++++
2 files changed, 115 insertions(+)
diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 3f013a513770..c8cc46f80a16 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -4,6 +4,13 @@
#include <linux/const.h>
#include <linux/types.h>
+#include <linux/in.h> /* for sockaddr_in */
+#include <linux/in6.h> /* for sockaddr_in6 */
+#include <linux/socket.h> /* for sockaddr_storage and sa_family */
+
+#ifndef __KERNEL__
+#include <sys/socket.h> /* for struct sockaddr */
+#endif
#define MPTCP_SUBFLOW_FLAG_MCAP_REM _BITUL(0)
#define MPTCP_SUBFLOW_FLAG_MCAP_LOC _BITUL(1)
@@ -200,8 +207,25 @@ struct mptcp_subflow_data {
__u32 size_user; /* size of one element in data[] */
} __attribute__((aligned(8)));
+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 __kernel_sockaddr_storage ss_local;
+ };
+ union {
+ struct sockaddr sa_remote;
+ struct sockaddr_in sin_remote;
+ struct sockaddr_in6 sin6_remote;
+ struct __kernel_sockaddr_storage ss_remote;
+ };
+};
+
/* MPTCP socket options */
#define MPTCP_INFO 1
#define MPTCP_TCPINFO 2
+#define MPTCP_SUBFLOW_ADDRS 3
#endif /* _UAPI_MPTCP_H */
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index eb2905bfa089..8137cc3a4296 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -840,6 +840,95 @@ static int mptcp_getsockopt_tcpinfo(struct mptcp_sock *msk, char __user *optval,
return 0;
}
+static void mptcp_get_sub_addrs(const struct sock *sk, struct mptcp_subflow_addrs *a)
+{
+ struct inet_sock *inet = inet_sk(sk);
+
+ memset(a, 0, sizeof(*a));
+
+ if (sk->sk_family == AF_INET) {
+ a->sin_local.sin_family = AF_INET;
+ a->sin_local.sin_port = inet->inet_sport;
+ a->sin_local.sin_addr.s_addr = inet->inet_rcv_saddr;
+
+ if (!a->sin_local.sin_addr.s_addr)
+ a->sin_local.sin_addr.s_addr = inet->inet_saddr;
+
+ a->sin_remote.sin_family = AF_INET;
+ a->sin_remote.sin_port = inet->inet_dport;
+ a->sin_remote.sin_addr.s_addr = inet->inet_daddr;
+#if IS_ENABLED(CONFIG_IPV6)
+ } else if (sk->sk_family == AF_INET6) {
+ const struct ipv6_pinfo *np = inet6_sk(sk);
+
+ a->sin6_local.sin6_family = AF_INET6;
+ a->sin6_local.sin6_port = inet->inet_sport;
+
+ if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
+ a->sin6_local.sin6_addr = np->saddr;
+ else
+ a->sin6_local.sin6_addr = sk->sk_v6_rcv_saddr;
+
+ a->sin6_remote.sin6_family = AF_INET6;
+ a->sin6_remote.sin6_port = inet->inet_dport;
+ a->sin6_remote.sin6_addr = sk->sk_v6_daddr;
+#endif
+ }
+}
+
+static int mptcp_getsockopt_subflow_addrs(struct mptcp_sock *msk, char __user *optval,
+ int __user *optlen)
+{
+ struct sock *sk = &msk->sk.icsk_inet.sk;
+ struct mptcp_subflow_context *subflow;
+ unsigned int sfcount = 0, copied = 0;
+ struct mptcp_subflow_data sfd;
+ char __user *addrptr;
+ int len;
+
+ len = mptcp_get_subflow_data(&sfd, optval, optlen);
+ if (len < 0)
+ return len;
+
+ sfd.size_kernel = sizeof(struct mptcp_subflow_addrs);
+ sfd.size_user = min_t(unsigned int, sfd.size_user,
+ sizeof(struct mptcp_subflow_addrs));
+
+ addrptr = optval + sfd.size_subflow_data;
+
+ lock_sock(sk);
+
+ mptcp_for_each_subflow(msk, subflow) {
+ struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+
+ ++sfcount;
+
+ if (len && len >= sfd.size_user) {
+ struct mptcp_subflow_addrs a;
+
+ mptcp_get_sub_addrs(ssk, &a);
+
+ if (copy_to_user(addrptr, &a, sfd.size_user)) {
+ release_sock(sk);
+ return -EFAULT;
+ }
+
+ addrptr += sfd.size_user;
+ copied += sfd.size_user;
+ len -= sfd.size_user;
+ }
+ }
+
+ release_sock(sk);
+
+ sfd.num_subflows = sfcount;
+
+ if (mptcp_put_subflow_data(&sfd, optval, copied, optlen))
+ return -EFAULT;
+
+ return 0;
+}
+
static int mptcp_getsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
char __user *optval, int __user *optlen)
{
@@ -862,6 +951,8 @@ static int mptcp_getsockopt_sol_mptcp(struct mptcp_sock *msk, int optname,
return mptcp_getsockopt_info(msk, optval, optlen);
case MPTCP_TCPINFO:
return mptcp_getsockopt_tcpinfo(msk, optval, optlen);
+ case MPTCP_SUBFLOW_ADDRS:
+ return mptcp_getsockopt_subflow_addrs(msk, optval, optlen);
}
return -EOPNOTSUPP;
--
2.33.0
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