From c11c5906bc0aba62a78da69035f6b30c6da6d13b Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 17 Sep 2021 16:33:21 -0700 Subject: 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 Signed-off-by: Matthieu Baerts Signed-off-by: Florian Westphal Signed-off-by: Mat Martineau Signed-off-by: David S. Miller --- include/uapi/linux/mptcp.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'include/uapi') 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 #include +#include /* for sockaddr_in */ +#include /* for sockaddr_in6 */ +#include /* for sockaddr_storage and sa_family */ + +#ifndef __KERNEL__ +#include /* 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 */ -- cgit v1.2.3-59-g8ed1b