diff options
Diffstat (limited to 'src/iftable.c')
-rw-r--r-- | src/iftable.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/src/iftable.c b/src/iftable.c new file mode 100644 index 0000000..0325335 --- /dev/null +++ b/src/iftable.c @@ -0,0 +1,335 @@ +/* iftable - table of network interfaces + * + * (C) 2004 by Astaro AG, written by Harald Welte <hwelte@astaro.com> + * (C) 2008 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * This software is Free Software and licensed under GNU GPLv2. + */ + +/* IFINDEX handling */ + +#include <unistd.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <sys/types.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <errno.h> +#include <assert.h> + +#include <linux/netdevice.h> + +#include <libnfnetlink/libnfnetlink.h> +#include "rtnl.h" +#include "linux_list.h" + +struct ifindex_node { + struct list_head head; + + u_int32_t index; + u_int32_t type; + u_int32_t alen; + u_int32_t flags; + char addr[8]; + char name[16]; +}; + +struct nlif_handle { + struct list_head ifindex_hash[16]; + struct rtnl_handle *rtnl_handle; + struct rtnl_handler ifadd_handler; + struct rtnl_handler ifdel_handler; +}; + +/* iftable_add - Add/Update an entry to/in the interface table + * @n: netlink message header of a RTM_NEWLINK message + * @arg: not used + * + * This function adds/updates an entry in the intrface table. + * Returns -1 on error, 1 on success. + */ +static int iftable_add(struct nlmsghdr *n, void *arg) +{ + unsigned int hash, found = 0; + struct ifinfomsg *ifi_msg = NLMSG_DATA(n); + struct ifindex_node *this; + struct rtattr *cb[IFLA_MAX+1]; + struct nlif_handle *h = arg; + + if (n->nlmsg_type != RTM_NEWLINK) + return -1; + + if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi_msg))) + return -1; + + rtnl_parse_rtattr(cb, IFLA_MAX, IFLA_RTA(ifi_msg), IFLA_PAYLOAD(n)); + + if (!cb[IFLA_IFNAME]) + return -1; + + hash = ifi_msg->ifi_index & 0xF; + list_for_each_entry(this, &h->ifindex_hash[hash], head) { + if (this->index == ifi_msg->ifi_index) { + found = 1; + break; + } + } + + if (!found) { + this = malloc(sizeof(*this)); + if (!this) + return -1; + + this->index = ifi_msg->ifi_index; + } + + this->type = ifi_msg->ifi_type; + this->flags = ifi_msg->ifi_flags; + if (cb[IFLA_ADDRESS]) { + unsigned int alen; + this->alen = alen = RTA_PAYLOAD(cb[IFLA_ADDRESS]); + if (alen > sizeof(this->addr)) + alen = sizeof(this->addr); + memcpy(this->addr, RTA_DATA(cb[IFLA_ADDRESS]), alen); + } else { + this->alen = 0; + memset(this->addr, 0, sizeof(this->addr)); + } + strcpy(this->name, RTA_DATA(cb[IFLA_IFNAME])); + + if (!found) + list_add(&this->head, &h->ifindex_hash[hash]); + + return 1; +} + +/* iftable_del - Delete an entry from the interface table + * @n: netlink message header of a RTM_DELLINK nlmsg + * @arg: not used + * + * Delete an entry from the interface table. + * Returns -1 on error, 0 if no matching entry was found or 1 on success. + */ +static int iftable_del(struct nlmsghdr *n, void *arg) +{ + struct ifinfomsg *ifi_msg = NLMSG_DATA(n); + struct rtattr *cb[IFLA_MAX+1]; + struct nlif_handle *h = arg; + struct ifindex_node *this, *tmp; + unsigned int hash; + + if (n->nlmsg_type != RTM_DELLINK) + return -1; + + if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi_msg))) + return -1; + + rtnl_parse_rtattr(cb, IFLA_MAX, IFLA_RTA(ifi_msg), IFLA_PAYLOAD(n)); + + hash = ifi_msg->ifi_index & 0xF; + list_for_each_entry_safe(this, tmp, &h->ifindex_hash[hash], head) { + if (this->index == ifi_msg->ifi_index) { + list_del(&this->head); + free(this); + return 1; + } + } + + return 0; +} + +/** Get the name for an ifindex + * + * \param nlif_handle A pointer to a ::nlif_handle created + * \param index ifindex to be resolved + * \param name interface name, pass a buffer of IFNAMSIZ size + * \return -1 on error, 1 on success + */ +int nlif_index2name(struct nlif_handle *h, + unsigned int index, + char *name) +{ + unsigned int hash; + struct ifindex_node *this; + + assert(h != NULL); + assert(name != NULL); + + if (index == 0) { + strcpy(name, "*"); + return 1; + } + + hash = index & 0xF; + list_for_each_entry(this, &h->ifindex_hash[hash], head) { + if (this->index == index) { + strcpy(name, this->name); + return 1; + } + } + + errno = ENOENT; + return -1; +} + +/** Get the flags for an ifindex + * + * \param nlif_handle A pointer to a ::nlif_handle created + * \param index ifindex to be resolved + * \param flags pointer to variable used to store the interface flags + * \return -1 on error, 1 on success + */ +int nlif_get_ifflags(const struct nlif_handle *h, + unsigned int index, + unsigned int *flags) +{ + unsigned int hash; + struct ifindex_node *this; + + assert(h != NULL); + assert(flags != NULL); + + if (index == 0) { + errno = ENOENT; + return -1; + } + + hash = index & 0xF; + list_for_each_entry(this, &h->ifindex_hash[hash], head) { + if (this->index == index) { + *flags = this->flags; + return 1; + } + } + errno = ENOENT; + return -1; +} + +/** Initialize interface table + * + * Initialize rtnl interface and interface table + * Call this before any nlif_* function + * + * \return file descriptor to netlink socket + */ +struct nlif_handle *nlif_open(void) +{ + int i; + struct nlif_handle *h; + + h = calloc(1, sizeof(struct nlif_handle)); + if (h == NULL) + goto err; + + for (i=0; i<16; i++) + INIT_LIST_HEAD(&h->ifindex_hash[i]); + + h->ifadd_handler.nlmsg_type = RTM_NEWLINK; + h->ifadd_handler.handlefn = iftable_add; + h->ifadd_handler.arg = h; + h->ifdel_handler.nlmsg_type = RTM_DELLINK; + h->ifdel_handler.handlefn = iftable_del; + h->ifdel_handler.arg = h; + + h->rtnl_handle = rtnl_open(); + if (h->rtnl_handle == NULL) + goto err; + + if (rtnl_handler_register(h->rtnl_handle, &h->ifadd_handler) < 0) + goto err_close; + + if (rtnl_handler_register(h->rtnl_handle, &h->ifdel_handler) < 0) + goto err_unregister; + + return h; + +err_unregister: + rtnl_handler_unregister(h->rtnl_handle, &h->ifadd_handler); +err_close: + rtnl_close(h->rtnl_handle); + free(h); +err: + return NULL; +} + +/** Destructor of interface table + * + * \param nlif_handle A pointer to a ::nlif_handle created + * via nlif_open() + */ +void nlif_close(struct nlif_handle *h) +{ + int i; + struct ifindex_node *this, *tmp; + + assert(h != NULL); + + rtnl_handler_unregister(h->rtnl_handle, &h->ifadd_handler); + rtnl_handler_unregister(h->rtnl_handle, &h->ifdel_handler); + rtnl_close(h->rtnl_handle); + + for (i=0; i<16; i++) { + list_for_each_entry_safe(this, tmp, &h->ifindex_hash[i], head) { + list_del(&this->head); + free(this); + } + } + + free(h); + h = NULL; /* bugtrap */ +} + +/** Receive message from netlink and update interface table + * + * \param nlif_handle A pointer to a ::nlif_handle created + * \return 0 if OK + */ +int nlif_catch(struct nlif_handle *h) +{ + assert(h != NULL); + + if (h->rtnl_handle) + return rtnl_receive(h->rtnl_handle); + + return -1; +} + +static int nlif_catch_multi(struct nlif_handle *h) +{ + assert(h != NULL); + + if (h->rtnl_handle) + return rtnl_receive_multi(h->rtnl_handle); + + return -1; +} + +/** + * nlif_query - request a dump of interfaces available in the system + * @h: pointer to a valid nlif_handler + */ +int nlif_query(struct nlif_handle *h) +{ + assert(h != NULL); + + if (rtnl_dump_type(h->rtnl_handle, RTM_GETLINK) < 0) + return -1; + + return nlif_catch_multi(h); +} + +/** Returns socket descriptor for the netlink socket + * + * \param nlif_handle A pointer to a ::nlif_handle created + * \return The fd or -1 if there's an error + */ +int nlif_fd(struct nlif_handle *h) +{ + assert(h != NULL); + + if (h->rtnl_handle) + return h->rtnl_handle->rtnl_fd; + + return -1; +} |