From e374664f48724e5b13a848bad5c5353349f0ae38 Mon Sep 17 00:00:00 2001 From: Ken-ichirou MATSUZAWA Date: Thu, 25 Sep 2014 09:33:27 +0900 Subject: socket: creating a struct mnl_socket from a pre-existing socket This patch defines a new function mnl_socket_fdopen() which creates a struct mnl_socket object from a pre-existing socket like obtained from other process and different domain/type from the same prodess. Signed-off-by: Ken-ichirou MATSUZAWA Signed-off-by: Pablo Neira Ayuso --- include/libmnl/libmnl.h | 1 + src/libmnl.map | 4 ++++ src/socket.c | 34 ++++++++++++++++++++++++++++++++++ 3 files changed, 39 insertions(+) diff --git a/include/libmnl/libmnl.h b/include/libmnl/libmnl.h index 223709c..0de6678 100644 --- a/include/libmnl/libmnl.h +++ b/include/libmnl/libmnl.h @@ -22,6 +22,7 @@ extern "C" { struct mnl_socket; extern struct mnl_socket *mnl_socket_open(int type); +extern struct mnl_socket *mnl_socket_fdopen(int fd); extern int mnl_socket_bind(struct mnl_socket *nl, unsigned int groups, pid_t pid); extern int mnl_socket_close(struct mnl_socket *nl); extern int mnl_socket_get_fd(const struct mnl_socket *nl); diff --git a/src/libmnl.map b/src/libmnl.map index dbc332e..3c147a7 100644 --- a/src/libmnl.map +++ b/src/libmnl.map @@ -72,3 +72,7 @@ local: *; LIBMNL_1.1 { mnl_attr_parse_payload; } LIBMNL_1.0; + +LIBMNL_1.2 { + mnl_socket_fdopen; +} LIBMNL_1.1; diff --git a/src/socket.c b/src/socket.c index 0c3cd72..86657d4 100644 --- a/src/socket.c +++ b/src/socket.c @@ -128,6 +128,40 @@ struct mnl_socket *mnl_socket_open(int bus) } EXPORT_SYMBOL(mnl_socket_open); +/** + * mnl_socket_fdopen - associates a mnl_socket object with pre-existing socket. + * \param fd pre-existing socket descriptor. + * + * On error, it returns NULL and errno is appropriately set. Otherwise, it + * returns a valid pointer to the mnl_socket structure. It also sets the portID + * if the socket fd is already bound and it is AF_NETLINK. + * + * Note that mnl_socket_get_portid() returns 0 if this function is used with + * non-netlink socket. + */ +struct mnl_socket *mnl_socket_fdopen(int fd) +{ + int ret; + struct mnl_socket *nl; + struct sockaddr_nl addr; + socklen_t addr_len = sizeof(struct sockaddr_nl); + + ret = getsockname(fd, (struct sockaddr *) &addr, &addr_len); + if (ret == -1) + return NULL; + + nl = calloc(1, sizeof(struct mnl_socket)); + if (nl == NULL) + return NULL; + + nl->fd = fd; + if (addr.nl_family == AF_NETLINK) + nl->addr = addr; + + return nl; +} +EXPORT_SYMBOL(mnl_socket_fdopen); + /** * mnl_socket_bind - bind netlink socket * \param nl netlink socket obtained via mnl_socket_open() -- cgit v1.2.3