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Diffstat (limited to 'include/osmocom/sgsn/gtphub.h')
| -rw-r--r-- | include/osmocom/sgsn/gtphub.h | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/include/osmocom/sgsn/gtphub.h b/include/osmocom/sgsn/gtphub.h new file mode 100644 index 000000000..8fd9f38cf --- /dev/null +++ b/include/osmocom/sgsn/gtphub.h @@ -0,0 +1,523 @@ +/* GTP Hub Implementation */ + +/* (C) 2015 by sysmocom s.f.m.c. GmbH <info@sysmocom.de> + * All Rights Reserved + * + * Author: Neels Hofmeyr + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation; either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#pragma once + +#include <stdint.h> +#include <sys/socket.h> + +#include <osmocom/core/select.h> +#include <osmocom/core/timer.h> +#include <osmocom/core/rate_ctr.h> + +#include <osmocom/sgsn/gprs_sgsn.h> + + +/* support */ + +/* TODO move to osmocom/core/socket.c ? */ +#include <netdb.h> /* for IPPROTO_* etc */ +struct osmo_sockaddr { + struct sockaddr_storage a; + socklen_t l; +}; + +/* TODO move to osmocom/core/socket.c ? */ +/*! \brief Initialize a sockaddr + * \param[out] addr Valid osmo_sockaddr pointer to write result to + * \param[in] family Address Family like AF_INET, AF_INET6, AF_UNSPEC + * \param[in] type Socket type like SOCK_DGRAM, SOCK_STREAM + * \param[in] proto Protocol like IPPROTO_TCP, IPPROTO_UDP + * \param[in] host Remote host name or IP address in string form + * \param[in] port Remote port number in host byte order + * \returns 0 on success, otherwise an error code (from getaddrinfo()). + * + * Copy the first result from a getaddrinfo() call with the given parameters to + * *addr and *addr_len. On error, do not change *addr and return nonzero. + */ +int osmo_sockaddr_init(struct osmo_sockaddr *addr, + uint16_t family, uint16_t type, uint8_t proto, + const char *host, uint16_t port); + +/* Conveniently pass AF_UNSPEC, SOCK_DGRAM and IPPROTO_UDP to + * osmo_sockaddr_init(). */ +static inline int osmo_sockaddr_init_udp(struct osmo_sockaddr *addr, + const char *host, uint16_t port) +{ + return osmo_sockaddr_init(addr, AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, + host, port); +} + +/*! \brief convert sockaddr to human readable string. + * \param[out] addr_str Valid pointer to a buffer of length addr_str_len. + * \param[in] addr_str_len Size of buffer addr_str points at. + * \param[out] port_str Valid pointer to a buffer of length port_str_len. + * \param[in] port_str_len Size of buffer port_str points at. + * \param[in] addr Binary representation as returned by osmo_sockaddr_init(). + * \param[in] flags flags as passed to getnameinfo(). + * \returns 0 on success, an error code on error. + * + * Return the IPv4 or IPv6 address string and the port (a.k.a. service) string + * representations of the given struct osmo_sockaddr in two caller provided + * char buffers. Flags of (NI_NUMERICHOST | NI_NUMERICSERV) return numeric + * address and port. Either one of addr_str or port_str may be NULL, in which + * case nothing is returned there. + * + * See also osmo_sockaddr_to_str() (less flexible, but much more convenient). */ +int osmo_sockaddr_to_strs(char *addr_str, size_t addr_str_len, + char *port_str, size_t port_str_len, + const struct osmo_sockaddr *addr, + int flags); + + +/*! \brief concatenate the parts returned by osmo_sockaddr_to_strs(). + * \param[in] addr Binary representation as returned by osmo_sockaddr_init(). + * \param[in] buf A buffer to use for string operations. + * \param[in] buf_len Length of the buffer. + * \returns Address string (in buffer). + * + * Compose a string of the numeric IP-address and port represented by *addr of + * the form "<ip-addr> port <port>". The returned string is valid until the + * next invocation of this function. + */ +const char *osmo_sockaddr_to_strb(const struct osmo_sockaddr *addr, + char *buf, size_t buf_len); + +/*! \brief conveniently return osmo_sockaddr_to_strb() in a static buffer. + * \param[in] addr Binary representation as returned by osmo_sockaddr_init(). + * \returns Address string in static buffer. + * + * See osmo_sockaddr_to_strb(). + * + * Note: only one osmo_sockaddr_to_str() call will work per print/log + * statement. For two or more, use osmo_sockaddr_to_strb() with a separate + * buffer each. + */ +const char *osmo_sockaddr_to_str(const struct osmo_sockaddr *addr); + +/*! \brief compare two osmo_sockaddr. + * \param[in] a The first address to compare. + * \param[in] b The other address to compare. + * \returns 0 if equal, otherwise -1 or 1. + */ +int osmo_sockaddr_cmp(const struct osmo_sockaddr *a, + const struct osmo_sockaddr *b); + +/*! \brief Overwrite *dst with *src. + * Like memcpy(), but copy only the valid bytes. */ +void osmo_sockaddr_copy(struct osmo_sockaddr *dst, + const struct osmo_sockaddr *src); + + +/* general */ + +enum gtphub_plane_idx { + GTPH_PLANE_CTRL = 0, + GTPH_PLANE_USER = 1, + GTPH_PLANE_N +}; + +enum gtphub_side_idx { + GTPH_SIDE_SGSN = 0, + GTPH_SIDE_GGSN = 1, + GTPH_SIDE_N +}; + +#define for_each_side(I) for (I = 0; I < GTPH_SIDE_N; I++) +#define for_each_plane(I) for (I = 0; I < GTPH_PLANE_N; I++) +#define for_each_side_and_plane(I,J) for_each_side(I) for_each_plane(J) + +static inline int other_side_idx(int side_idx) +{ + return (side_idx + 1) & 1; +} + +extern const char* const gtphub_plane_idx_names[GTPH_PLANE_N]; +extern const uint16_t gtphub_plane_idx_default_port[GTPH_PLANE_N]; + +extern const char* const gtphub_side_idx_names[GTPH_SIDE_N]; + +/* A host address in the form that is expected in the 7.7.32 GSN Address IE. + * len is either 4 (IPv4) or 16 (IPv6), any other value is invalid. If no + * address is set, len shall be 0. */ +struct gsn_addr { + uint16_t len; + uint8_t buf[16]; +}; + +void gsn_addr_copy(struct gsn_addr *gsna, const struct gsn_addr *src); +int gsn_addr_from_str(struct gsn_addr *gsna, const char *numeric_addr_str); + +/* Return gsna in numeric string form, in a static buffer. */ +const char *gsn_addr_to_str(const struct gsn_addr *gsna); + +/* note: strbuf_len doesn't need to be larger than INET6_ADDRSTRLEN + 1. */ +const char *gsn_addr_to_strb(const struct gsn_addr *gsna, + char *strbuf, int strbuf_len); + +/* Return 1 on match, zero otherwise. */ +int gsn_addr_same(const struct gsn_addr *a, const struct gsn_addr *b); + +/* Decode sa to gsna. Return 0 on success. If port is non-NULL, the port number + * from sa is also returned. */ +int gsn_addr_from_sockaddr(struct gsn_addr *gsna, uint16_t *port, + const struct osmo_sockaddr *sa); + +/* expiry */ + +struct expiring_item; +typedef void (*del_cb_t)(struct expiring_item *); + +struct expiring_item { + struct llist_head entry; + time_t expiry; + del_cb_t del_cb; +}; + +struct expiry { + int expiry_in_seconds; + struct llist_head items; +}; + +/* Initialize an expiry queue. */ +void expiry_init(struct expiry *exq, int expiry_in_seconds); + +/* Add a new mapping, or restart the expiry timeout for an already listed + * mapping. */ +void expiry_add(struct expiry *exq, struct expiring_item *item, time_t now); + +/* Initialize to all-empty; must be called before using the item in any way. */ +void expiring_item_init(struct expiring_item *item); + +/* Remove the given item from its expiry queue, and call item->del_cb, if set. + * This sets item->del_cb to NULL and is harmless when run a second time on the + * same item, so the del_cb may choose to call this function, too, to allow + * deleting items from several code paths. */ +void expiring_item_del(struct expiring_item *item); + +/* Carry out due expiry of mappings. Must be invoked regularly. + * 'now' is the current clock count in seconds and must correspond to the clock + * count passed to nr_map_add(). A monotonous clock counter should be used. */ +int expiry_tick(struct expiry *exq, time_t now); + +/* Expire all items. */ +void expiry_clear(struct expiry *exq); + + +/* number map */ + +/* A number map assigns a "random" mapped number to each user provided number. + * If the same number is requested multiple times, the same mapped number is + * returned. + * + * Number maps plug into possibly shared pools and expiry queues, for example: + * + * mapA -----------+-> pool1 <-+-- mapB + * {10->1, 11->5} | {1, 2, 3, ...} | {10->2, 11->3} + * | | + * | | + * /-> \-> expiry1 <-/ + * | (30 seconds) + * | + * mapC -------+-----> pool2 <-+-- mapD + * {10->1, 11->3} {1, 2, 3, ...} | {10->2, 11->5} + * | + * expiry2 <-/ + * (60 seconds) + * + * A map contains mappings ("10->1"). Each map needs a number pool, which can + * be shared with other maps. Each new mapping receives a number from the pool, + * which is then unavailable to any other map using the same pool. + * + * A map may point at an expiry queue, in which case all mappings added to it + * are also appended to the expiry queue (using a separate llist entry in the + * mapping). Any number of maps may submit to the same expiry queue, if they + * desire the same expiry timeout. An expiry queue stores the mappings in + * chronological order, so that expiry checking is needed only from the start + * of the queue; hence only mappings with identical expiry timeout can be added + * to the same expiry queue. Upon expiry, a mapping is dropped from the map it + * was submitted at. expiry_tick() needs to be called regularly for each expiry + * queue. + * + * A nr_mapping can be embedded in a larger struct: each mapping can have a + * distinct destructor (del_cb), and each del_cb can figure out the container + * struct's address and free that upon expiry or manual deletion. So in expiry + * queues (and even maps), mappings of different container types can be mixed. + * This can help to drastically reduce the amount of unnecessary visits during + * expiry checking, for the case that no expiry is pending. An expiry queue + * always knows which mappings to expire next, because they are right at the + * start of its list. + * + * Mapping allocation and a del_cb are provided by the caller. If del_cb is + * NULL, no deallocation will be done (allowing statically allocated entries). + */ + +typedef unsigned int nr_t; + +/* Generator for unused numbers. So far this counts upwards from zero, but the + * implementation may change in the future. Treat this like an opaque struct. + * If this becomes random, the tests need to be fixed. */ +struct nr_pool { + nr_t last_nr; + nr_t nr_min; + nr_t nr_max; +}; + +struct nr_mapping { + struct llist_head entry; + struct expiring_item expiry_entry; + + void *origin; + nr_t orig; + nr_t repl; +}; + +struct nr_map { + struct nr_pool *pool; /* multiple nr_maps can share a nr_pool. */ + struct expiry *add_items_to_expiry; + struct llist_head mappings; +}; + + +void nr_pool_init(struct nr_pool *pool, nr_t nr_min, nr_t nr_max); + +/* Return the next unused number from the nr_pool. */ +nr_t nr_pool_next(struct nr_pool *pool); + +/* Initialize the nr_mapping to zero/empty values. */ +void nr_mapping_init(struct nr_mapping *mapping); + +/* Remove the given mapping from its parent map and expiry queue, and call + * mapping->del_cb, if set. */ +void nr_mapping_del(struct nr_mapping *mapping); + +/* Initialize an (already allocated) nr_map, and set the map's number pool. + * Multiple nr_map instances may use the same nr_pool. Set the nr_map's expiry + * queue to exq, so that all added mappings are automatically expired after the + * time configured in exq. exq may be NULL to disable automatic expiry. */ +void nr_map_init(struct nr_map *map, struct nr_pool *pool, + struct expiry *exq); + +/* Add a new entry to the map. mapping->orig, mapping->origin and + * mapping->del_cb must be set before calling this function. The remaining + * fields of *mapping will be overwritten. mapping->repl is set to the next + * available mapped number from map->pool. 'now' is the current clock count in + * seconds; if no map->expiry is used, just pass 0 for 'now'. */ +void nr_map_add(struct nr_map *map, struct nr_mapping *mapping, + time_t now); + +/* Restart the timeout for the given mapping. mapping must be a member of map. + */ +void nr_map_refresh(struct nr_map *map, struct nr_mapping *mapping, + time_t now); + +/* Return a known mapping from nr_orig and the given origin. If nr_orig is + * unknown, return NULL. */ +struct nr_mapping *nr_map_get(const struct nr_map *map, + void *origin, nr_t nr_orig); + +/* Return a known mapping to nr_repl. If nr_repl is unknown, return NULL. */ +struct nr_mapping *nr_map_get_inv(const struct nr_map *map, nr_t nr_repl); + +/* Remove all mappings from map. */ +void nr_map_clear(struct nr_map *map); + +/* Return 1 if map has no entries, 0 otherwise. */ +int nr_map_empty(const struct nr_map *map); + + +/* config */ + +static const int GTPH_EXPIRE_QUICKLY_SECS = 30; /* TODO is there a spec for this? */ +static const int GTPH_EXPIRE_SLOWLY_MINUTES = 6 * 60; /* TODO is there a spec for this? */ + +struct gtphub_cfg_addr { + const char *addr_str; + uint16_t port; +}; + +struct gtphub_cfg_bind { + struct gtphub_cfg_addr bind; +}; + +struct gtphub_cfg { + struct gtphub_cfg_bind to_gsns[GTPH_SIDE_N][GTPH_PLANE_N]; + struct gtphub_cfg_addr proxy[GTPH_SIDE_N][GTPH_PLANE_N]; + int sgsn_use_sender; /* Use sender, not GSN addr IE with std ports */ +}; + + +/* state */ + +struct gtphub_peer { + struct llist_head entry; + + struct llist_head addresses; /* Alternatives, not load balancing. */ + struct nr_pool seq_pool; + struct nr_map seq_map; +}; + +struct gtphub_peer_addr { + struct llist_head entry; + + struct gtphub_peer *peer; + struct gsn_addr addr; + struct llist_head ports; +}; + +struct gtphub_peer_port { + struct llist_head entry; + + struct gtphub_peer_addr *peer_addr; + uint16_t port; + unsigned int ref_count; /* references from other peers' seq_maps */ + struct osmo_sockaddr sa; /* a "cache" for (peer_addr->addr, port) */ + int last_restart_count; /* 0..255 = valid, all else means unknown */ + + struct rate_ctr_group *counters_io; +}; + +struct gtphub_tunnel_endpoint { + struct gtphub_peer_port *peer; + uint32_t tei_orig; /* from/to peer */ + + struct rate_ctr_group *counters_io; +}; + +struct gtphub_tunnel { + struct llist_head entry; + struct expiring_item expiry_entry; + + uint32_t tei_repl; /* unique TEI to replace peers' TEIs */ + struct gtphub_tunnel_endpoint endpoint[GTPH_SIDE_N][GTPH_PLANE_N]; +}; + +struct gtphub_bind { + struct gsn_addr local_addr; + uint16_t local_port; + struct osmo_fd ofd; + + /* list of struct gtphub_peer */ + struct llist_head peers; + + const char *label; /* For logging */ + struct rate_ctr_group *counters_io; +}; + +struct gtphub_resolved_ggsn { + struct llist_head entry; + struct expiring_item expiry_entry; + + /* The APN OI, the Operator Identifier, is the combined address, + * including parts of the IMSI and APN NI, and ending with ".gprs". */ + char apn_oi_str[GSM_APN_LENGTH]; + + /* Which address and port we resolved that to. */ + struct gtphub_peer_port *peer; +}; + +struct gtphub { + struct gtphub_bind to_gsns[GTPH_SIDE_N][GTPH_PLANE_N]; + + /* pointers to an entry of to_gsns[s][p].peers */ + struct gtphub_peer_port *proxy[GTPH_SIDE_N][GTPH_PLANE_N]; + + /* The TEI numbers will simply wrap and be reused, which will work out + * in practice. Problems would arise if one given peer maintained the + * same TEI for a time long enough for the TEI nr map to wrap an entire + * uint32_t; if a new TEI were mapped every second, this would take + * more than 100 years (in which a single given TEI must not time out) + * to cause a problem. */ + struct nr_pool tei_pool; + + struct llist_head tunnels; /* struct gtphub_tunnel */ + struct llist_head pending_deletes; /* opaque (gtphub.c) */ + + struct llist_head ggsn_lookups; /* opaque (gtphub_ares.c) */ + struct llist_head resolved_ggsns; /* struct gtphub_resolved_ggsn */ + + struct osmo_timer_list gc_timer; + struct expiry expire_quickly; + struct expiry expire_slowly; + + uint8_t restart_counter; + + int sgsn_use_sender; +}; + +struct gtp_packet_desc; + + +/* api */ + +int gtphub_vty_init(struct gtphub *global_hub, struct gtphub_cfg *global_cfg); +int gtphub_cfg_read(struct gtphub_cfg *cfg, const char *config_file); + +/* Initialize and start gtphub: bind to ports, run expiry timers. */ +int gtphub_start(struct gtphub *hub, struct gtphub_cfg *cfg, + uint8_t restart_counter); + +/* Close all sockets, expire all maps and peers and free all allocations. The + * struct is then unusable, unless gtphub_start() is run on it again. */ +void gtphub_stop(struct gtphub *hub); + +time_t gtphub_now(void); + +/* Remove expired items, empty peers, ... */ +void gtphub_gc(struct gtphub *hub, time_t now); + +/* Return the string of the first address for this peer. */ +const char *gtphub_peer_str(struct gtphub_peer *peer); + +/* Return a human readable description of tun in a static buffer. */ +const char *gtphub_tunnel_str(struct gtphub_tunnel *tun); + +/* Return 1 if all of tun's endpoints are fully established, 0 otherwise. */ +int gtphub_tunnel_complete(struct gtphub_tunnel *tun); + +int gtphub_handle_buf(struct gtphub *hub, + unsigned int side_idx, + unsigned int port_idx, + const struct osmo_sockaddr *from_addr, + uint8_t *buf, + size_t received, + time_t now, + uint8_t **reply_buf, + struct osmo_fd **to_ofd, + struct osmo_sockaddr *to_addr); + +struct gtphub_peer_port *gtphub_port_have(struct gtphub *hub, + struct gtphub_bind *bind, + const struct gsn_addr *addr, + uint16_t port); + +struct gtphub_peer_port *gtphub_port_find_sa(const struct gtphub_bind *bind, + const struct osmo_sockaddr *addr); + +void gtphub_resolved_ggsn(struct gtphub *hub, const char *apn_oi_str, + struct gsn_addr *resolved_addr, + time_t now); + +const char *gtphub_port_str(struct gtphub_peer_port *port); + +int gtphub_write(const struct osmo_fd *to, + const struct osmo_sockaddr *to_addr, + const uint8_t *buf, size_t buf_len); |