diff mbox series

[v3,mptcp-next,4/5] mptcp: add MPTCP_SUBFLOW_ADDRS getsockopt support

Message ID 20210818102756.30734-5-fw@strlen.de (mailing list archive)
State Accepted, archived
Commit efd9c3320c756d41b2185edf8cbae347b99939ae
Delegated to: Matthieu Baerts
Headers show
Series mptcp: add SOL_MPTCP getsockopt support | expand

Commit Message

Florian Westphal Aug. 18, 2021, 10:27 a.m. UTC 
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.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 include/uapi/linux/mptcp.h | 17 +++++++
 net/mptcp/sockopt.c        | 91 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 108 insertions(+)

Comments

Geliang Tang Aug. 30, 2021, 4:18 a.m. UTC | #1 
Hello,

I got this compile error in my Fedora-34 system (export/20210829T054626):

  DESCEND objtool
  DESCEND bpf/resolve_btfids
  CALL    scripts/atomic/check-atomics.sh
  CALL    scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  HDRTEST usr/include/linux/mptcp.h
In file included from <command-line>:
./usr/include/linux/mptcp.h:207:33: error: field ‘sa_local’ has incomplete type
  207 |                 struct sockaddr sa_local;
      |                                 ^~~~~~~~
./usr/include/linux/mptcp.h:209:37: error: field ‘sin6_local’ has
incomplete type
  209 |                 struct sockaddr_in6 sin6_local;
      |                                     ^~~~~~~~~~
./usr/include/linux/mptcp.h:210:41: error: field ‘ss_local’ has incomplete type
  210 |                 struct sockaddr_storage ss_local;
      |                                         ^~~~~~~~
./usr/include/linux/mptcp.h:213:33: error: field ‘sa_remote’ has incomplete type
  213 |                 struct sockaddr sa_remote;
      |                                 ^~~~~~~~~
./usr/include/linux/mptcp.h:215:37: error: field ‘sin6_remote’ has
incomplete type
  215 |                 struct sockaddr_in6 sin6_remote;
      |                                     ^~~~~~~~~~~
./usr/include/linux/mptcp.h:216:41: error: field ‘ss_remote’ has incomplete type
  216 |                 struct sockaddr_storage ss_remote;
      |                                         ^~~~~~~~~
make[2]: *** [usr/include/Makefile:106: usr/include/linux/mptcp.hdrtest] Error 1
make[1]: *** [scripts/Makefile.build:514: usr/include] Error 2
make: *** [Makefile:1851: usr] Error 2
make: *** Waiting for unfinished jobs....

How can I fix it, please give me some suggestion.

Thanks,
-Geliang

Florian Westphal <fw@strlen.de> 于2021年8月18日周三 下午6:28写道：
>
> 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.
>
> Signed-off-by: Florian Westphal <fw@strlen.de>
> ---
>  include/uapi/linux/mptcp.h | 17 +++++++
>  net/mptcp/sockopt.c        | 91 ++++++++++++++++++++++++++++++++++++++
>  2 files changed, 108 insertions(+)
>
> diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
> index 7c368fccd83e..c368c11a0ed9 100644
> --- a/include/uapi/linux/mptcp.h
> +++ b/include/uapi/linux/mptcp.h
> @@ -201,8 +201,25 @@ 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 sockaddr_storage ss_local;
> +       };
> +       union {
> +               struct sockaddr sa_remote;
> +               struct sockaddr_in sin_remote;
> +               struct sockaddr_in6 sin6_remote;
> +               struct 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;
> --
> 2.31.1
>
>
diff mbox series

Patch

diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
index 7c368fccd83e..c368c11a0ed9 100644
--- a/include/uapi/linux/mptcp.h
+++ b/include/uapi/linux/mptcp.h
@@ -201,8 +201,25 @@  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 sockaddr_storage ss_local;
+	};
+	union {
+		struct sockaddr sa_remote;
+		struct sockaddr_in sin_remote;
+		struct sockaddr_in6 sin6_remote;
+		struct 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;