From: Paolo Abeni pabeni@redhat.com
Some user-space applications want to monitor the subflows utilization.
Dumping the per subflow tcp_info is not enough, as the PM could close and re-create the subflows under-the-hood, fooling the accounting. Even checking the src/dst addresses used by each subflow could not be enough, because new subflows could re-use the same address/port of the just closed one.
This patch introduces a new socket option, allow dumping all the relevant information all-at-once (everything, everywhere...), in a consistent manner.
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/388 Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net --- include/uapi/linux/mptcp.h | 24 +++++++++ net/mptcp/sockopt.c | 127 ++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 149 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h index a124be6ebbba..ee9c49f949a2 100644 --- a/include/uapi/linux/mptcp.h +++ b/include/uapi/linux/mptcp.h @@ -249,9 +249,33 @@ struct mptcp_subflow_addrs { }; };
+struct mptcp_subflow_info { + __u32 id; + struct mptcp_subflow_addrs addrs; +}; + +struct mptcp_full_info { + __u32 size_tcpinfo_kernel; /* must be 0, set by kernel */ + __u32 size_tcpinfo_user; + __u32 size_sfinfo_kernel; /* must be 0, set by kernel */ + __u32 size_sfinfo_user; + __u32 num_subflows; /* must be 0, set by kernel (real subflow count) */ + __u32 size_arrays_user; /* max subflows that userspace is interested in; + * the buffers at subflow_info/tcp_info + * are respectively at least: + * size_arrays * size_sfinfo_user + * size_arrays * size_tcpinfo_user + * bytes wide + */ + __aligned_u64 subflow_info; + __aligned_u64 tcp_info; + struct mptcp_info mptcp_info; +}; + /* MPTCP socket options */ #define MPTCP_INFO 1 #define MPTCP_TCPINFO 2 #define MPTCP_SUBFLOW_ADDRS 3 +#define MPTCP_FULL_INFO 4
#endif /* _UAPI_MPTCP_H */ diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index fa5055d5b029..63f7a09335c5 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -14,7 +14,8 @@ #include <net/mptcp.h> #include "protocol.h"
-#define MIN_INFO_OPTLEN_SIZE 16 +#define MIN_INFO_OPTLEN_SIZE 16 +#define MIN_FULL_INFO_OPTLEN_SIZE 40
static struct sock *__mptcp_tcp_fallback(struct mptcp_sock *msk) { @@ -981,7 +982,8 @@ static int mptcp_put_subflow_data(struct mptcp_subflow_data *sfd, }
static int mptcp_get_subflow_data(struct mptcp_subflow_data *sfd, - char __user *optval, int __user *optlen) + char __user *optval, + int __user *optlen) { int len, copylen;
@@ -1162,6 +1164,125 @@ static int mptcp_getsockopt_subflow_addrs(struct mptcp_sock *msk, char __user *o return 0; }
+static int mptcp_get_full_info(struct mptcp_full_info *mfi, + char __user *optval, + int __user *optlen) +{ + int len; + + BUILD_BUG_ON(offsetof(struct mptcp_full_info, mptcp_info) != + MIN_FULL_INFO_OPTLEN_SIZE); + + if (get_user(len, optlen)) + return -EFAULT; + + if (len < MIN_FULL_INFO_OPTLEN_SIZE) + return -EINVAL; + + memset(mfi, 0, sizeof(*mfi)); + if (copy_from_user(mfi, optval, MIN_FULL_INFO_OPTLEN_SIZE)) + return -EFAULT; + + if (mfi->size_tcpinfo_kernel || + mfi->size_sfinfo_kernel || + mfi->num_subflows) + return -EINVAL; + + if (mfi->size_sfinfo_user > INT_MAX || + mfi->size_tcpinfo_user > INT_MAX) + return -EINVAL; + + return len - MIN_FULL_INFO_OPTLEN_SIZE; +} + +static int mptcp_put_full_info(struct mptcp_full_info *mfi, + char __user *optval, + u32 copylen, + int __user *optlen) +{ + copylen += MIN_FULL_INFO_OPTLEN_SIZE; + if (put_user(copylen, optlen)) + return -EFAULT; + + if (copy_to_user(optval, mfi, copylen)) + return -EFAULT; + return 0; +} + +static int mptcp_getsockopt_full_info(struct mptcp_sock *msk, char __user *optval, + int __user *optlen) +{ + unsigned int sfcount = 0, copylen = 0; + struct mptcp_subflow_context *subflow; + struct sock *sk = (struct sock *)msk; + void __user *tcpinfoptr, *sfinfoptr; + struct mptcp_full_info mfi; + int len; + + len = mptcp_get_full_info(&mfi, optval, optlen); + if (len < 0) + return len; + + /* don't bother filling the mptcp info if there is not enough + * user-space-provided storage + */ + if (len > 0) { + mptcp_diag_fill_info(msk, &mfi.mptcp_info); + copylen += min_t(unsigned int, len, sizeof(struct mptcp_info)); + } + + mfi.size_tcpinfo_kernel = sizeof(struct tcp_info); + mfi.size_tcpinfo_user = min_t(unsigned int, mfi.size_tcpinfo_user, + sizeof(struct tcp_info)); + sfinfoptr = u64_to_user_ptr(mfi.subflow_info); + mfi.size_sfinfo_kernel = sizeof(struct mptcp_subflow_info); + mfi.size_sfinfo_user = min_t(unsigned int, mfi.size_sfinfo_user, + sizeof(struct mptcp_subflow_info)); + tcpinfoptr = u64_to_user_ptr(mfi.tcp_info); + + lock_sock(sk); + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + struct mptcp_subflow_info sfinfo; + struct tcp_info tcp_info; + + if (sfcount++ >= mfi.size_arrays_user) + continue; + + /* fetch addr/tcp_info only if the user space buffers + * are wide enough + */ + memset(&sfinfo, 0, sizeof(sfinfo)); + sfinfo.id = subflow->subflow_id; + if (mfi.size_sfinfo_user > + offsetof(struct mptcp_subflow_info, addrs)) + mptcp_get_sub_addrs(ssk, &sfinfo.addrs); + if (copy_to_user(sfinfoptr, &sfinfo, mfi.size_sfinfo_user)) + goto fail_release; + + if (mfi.size_tcpinfo_user) { + tcp_get_info(ssk, &tcp_info); + if (copy_to_user(tcpinfoptr, &tcp_info, + mfi.size_tcpinfo_user)) + goto fail_release; + } + + tcpinfoptr += mfi.size_tcpinfo_user; + sfinfoptr += mfi.size_sfinfo_user; + } + release_sock(sk); + + mfi.num_subflows = sfcount; + if (mptcp_put_full_info(&mfi, optval, copylen, optlen)) + return -EFAULT; + + return 0; + +fail_release: + release_sock(sk); + return -EFAULT; +} + static int mptcp_put_int_option(struct mptcp_sock *msk, char __user *optval, int __user *optlen, int val) { @@ -1235,6 +1356,8 @@ static int mptcp_getsockopt_sol_mptcp(struct mptcp_sock *msk, int optname, switch (optname) { case MPTCP_INFO: return mptcp_getsockopt_info(msk, optval, optlen); + case MPTCP_FULL_INFO: + return mptcp_getsockopt_full_info(msk, optval, optlen); case MPTCP_TCPINFO: return mptcp_getsockopt_tcpinfo(msk, optval, optlen); case MPTCP_SUBFLOW_ADDRS: