diff options
Diffstat (limited to 'server/tcp.c')
| -rw-r--r-- | server/tcp.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/server/tcp.c b/server/tcp.c new file mode 100644 index 0000000..0d6e118 --- /dev/null +++ b/server/tcp.c @@ -0,0 +1,285 @@ +#include "tcp.h" +#include <errno.h> +#include <netinet/in.h> +#include <stddef.h> + +#define report_error(socket, error) \ + do { \ + DEBUGF("error on socket %i: %i\n", socket, error); \ + write(socket, &zerozu, sizeof(zerozu)); \ + enum commd_error __ecpy = htonl(error); \ + write(socket, &__ecpy, sizeof(__ecpy)); \ + return; \ + } while (0) + +#define return_error(err) \ + do { \ + *e = err; \ + return 0; \ + } while (0) + +struct hash_set channels; +struct hash_set users; +static struct tcp_user varusr = {0}; +static struct tcp_channel varchnl = {0}; +static u64 lalloc_usr = 0; +static int udpctlfd = 0; +static const size_t zerozu = 0; +static bool should_exit = false; + +void print_state(int _) { + (void)_; +#ifdef DEBUG + fputs("printing server state.\n hash_map<struct tcp_user> users {\n", stderr); + struct hash_set_iter iter; + for (hseti_begin(&users, &iter); !hseti_end(&iter); hseti_next(&iter)) { + struct tcp_user *curr = hseti_get(&iter); + fprintf(stderr, "\ttcp_user {.id=%zu, .permissions=%u, .channel=%zu}\n", curr->id, curr->permissions, + curr->joined_channel); + } + fputs("}\nhash_map<struct tcp_channel> channels {\n", stderr); + for (hseti_begin(&channels, &iter); !hseti_end(&iter); hseti_next(&iter)) { + struct tcp_channel *curr = hseti_get(&iter); + struct sockaddr_in addr; + socklen_t addrlen = sizeof(addr); + getsockname(curr->fd, (struct sockaddr *)&addr, &addrlen); + fprintf(stderr, "\ttcp_channel {.id=%zu, .fd=%u, .channel=%zu} [port=%hu]\n", curr->id, curr->fd, + curr->owner, addr.sin_port); + } + fputs("}\n", stderr); +#endif +} +void exit_tcp(int _) { + (void)_; + should_exit = true; + DEBUGF("EXITING SERVER, setting `should_exit (%p)` to %i\n", (void*)&should_exit, (int)should_exit); +} + +static int tcp_user_cmp(const struct tcp_user *a, const struct tcp_user *b) { return (a->id - b->id) ? 1 : 0; } +static int tcp_channel_cmp(const struct tcp_channel *a, const struct tcp_channel *b) { return (a->id - b->id) ? 1 : 0; } +static size_t tcp_user_hash(const struct tcp_user *a) { return a->id; } +static size_t tcp_channel_hash(const struct tcp_channel *a) { return a->id; } +static int set_sock_timeout(int fd, int ms) { + struct timeval timeout; + timeout.tv_sec = ms / 1000; + timeout.tv_usec = (ms % 1000) * 1000; + return setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)); +} +static void init_statics(void) { + channels = + hset_new(sizeof(struct tcp_channel), (hset_equal_fn)&tcp_channel_cmp, (hset_hash_fn)&tcp_channel_hash); + users = hset_new(sizeof(struct tcp_user), (hset_equal_fn)&tcp_user_cmp, (hset_hash_fn)&tcp_user_hash); + udpctlfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); +} +static int setup_socket(unsigned short port) { + int sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); + int flag = 1; + if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof flag)) goto error; + struct sockaddr_in localaddr = { + .sin_family = AF_INET, .sin_port = htons(port), .sin_addr = {htonl(INADDR_ANY)}}; + if (bind(sock, (struct sockaddr *)&localaddr, sizeof(localaddr))) goto error; + return sock; +error: + perror("TCP thread failed to initialize"); + exit(EXIT_FAILURE); + +} +static void init_admin(u64 aid) { + struct tcp_user u = {.id = aid, .pubkey = NULL, .permissions = perm_admin, .joined_channel = 0}; + hset_insert_copy(&users, &u); +} +static bool has_4bytes_0xff(u64 id) { + return (unsigned int)(id >> 32) == 0xFFFFFFFF || (unsigned int)(id & 0xFFFFFFFF) == 0xFFFFFFFF; +} +static u64 get_uniq_id(struct hash_set *set) { + // while (map has lalloc_usr inex || lalloc_usr has 4 bytes of ones) next lalloc_usr; + varusr.id = lalloc_usr; + while (hset_at(set, &varusr) != NULL || has_4bytes_0xff(lalloc_usr)) ++varusr.id; + lalloc_usr = varusr.id; + return lalloc_usr; +} +static unsigned short get_channel_port(u64 id) { + varchnl.id = id; + struct tcp_channel *ch = hset_at(&channels, &varchnl); + if (ch == NULL) return 0; + struct sockaddr_in a; + socklen_t len = sizeof a; + getsockname(ch->fd, (struct sockaddr *)&a, &len); + return a.sin_port; +} +static bool user_has_permission(u64 uid, unsigned int perm) { + varusr.id = uid; + struct tcp_user *u = hset_at(&users, &varusr); + if (u == NULL) return false; + unsigned int uperm = u->permissions; + // bitwise implication must yield all ones (0xFFFFFFFF). + // Inverse it for easier check + return (perm & ~uperm) == 0; +} +static u64 send_channels(int sockfd, enum commd_error *e) { + struct hash_set_iter iter; + u64 array_length = hton64(hset_count(&channels)); + if (write(sockfd, &array_length, sizeof(array_length)) != sizeof(array_length)) return_error(ERR_SERV); + for (hseti_begin(&channels, &iter); !hseti_end(&iter); hseti_next(&iter)) { + struct tcp_channel *c = hseti_get(&iter); + u64 chid = hton64(c->id); + if (write(sockfd, &chid, sizeof(chid)) != sizeof(chid)) return_error(ERR_SERV); + } + // the leading zero is written by the caller + return_error(ERR_SUCCESS); // actually returns success but... +} +static inline u64 commd_register_process(struct commd_register *cmd, enum commd_error *e) { + /* fprintf(stderr, "%s: auid=%zu; perm=%zu\n", "commd_register_process", cmd->auid, cmd->perm); */ + if (!user_has_permission(cmd->auid, perm_join_user | cmd->perm)) return_error(ERR_ACCESS); + struct tcp_user new_user = { + .id = get_uniq_id(&users), .joined_channel = 0, .permissions = (unsigned int)cmd->perm}; + hset_insert_copy(&users, &new_user); + return new_user.id; +} +static inline u64 commd_unregister_process(struct commd_unregister *cmd, enum commd_error *e) { + /* DEBUGF("delete user %zu (admin %zu)\n", cmd->uid, cmd->auid); */ + if (cmd->auid != cmd->uid && !user_has_permission(cmd->auid, perm_unregister_user)) return_error(ERR_ACCESS); + varusr.id = cmd->uid; + hset_remove(&users, &varusr); + return cmd->uid; +} +static inline u64 commd_create_process(struct commd_create *cmd, enum commd_error *e) { + if (!user_has_permission(cmd->uid, perm_add_channel)) return_error(ERR_ACCESS); + + u64 chid; + int sock = -1; + unsigned short port = 0; + { + pthread_mutex_t sock_mx = PTHREAD_MUTEX_INITIALIZER; + pthread_cond_t sock_cond = PTHREAD_COND_INITIALIZER; + struct thread_loop_arg arg = { + .owner = cmd->uid, .sock_dest = &sock, .sock_mx = &sock_mx, .sock_ready_cond = &sock_cond}; + pthread_mutex_lock(&sock_mx); + chid = spawn_channel(&arg); + DEBUG("\n"); + while (sock == -1 || port == 0) pthread_cond_wait(&sock_cond, &sock_mx); + DEBUG("\n"); + pthread_mutex_unlock(&sock_mx); + } + struct tcp_channel new_channel = {.owner = cmd->uid, .name = NULL, .fd = sock}; + hset_insert_copy(&channels, &new_channel); + return chid; +} +static inline u64 commd_delete_process(struct commd_delete *cmd, enum commd_error *e) { + DEBUGF("received command%p\n", (void *)cmd); + varchnl.id = cmd->chid; + struct tcp_channel *c = hset_at(&channels, &varchnl); + if (c == NULL) return_error(ERR_PARAM); + if (cmd->uid != c->owner && !user_has_permission(cmd->uid, perm_unadd_channel)) return_error(ERR_ACCESS); + hset_remove(&channels, &varchnl); + return varchnl.id; +} +static inline u64 commd_join_process(struct commd_join *cmd, enum commd_error *e) { + if (cmd->uid != cmd->juid && !user_has_permission(cmd->uid, perm_join_user)) return_error(ERR_ACCESS); + struct kv_system_packet packet = { + .magic_bytes = SYS_PACKET_MAGIC_BYTES, .operation_id = htonl(SYS_JOIN), .user_id = cmd->juid}; + if (!sendto_channel(cmd->chid, &packet, TCP_MAX_WAIT_MS, TCP_MAX_RETRIES)) return_error(ERR_SERV); + return (u64)get_channel_port(cmd->chid); +} +static inline u64 commd_leave_process(struct commd_leave *cmd, enum commd_error *e) { + if (cmd->uid != cmd->luid && !user_has_permission(cmd->uid, perm_kick_user)) return_error(ERR_ACCESS); + struct kv_system_packet packet = { + .magic_bytes = SYS_PACKET_MAGIC_BYTES, .operation_id = htonl(SYS_LEAVE), .user_id = cmd->luid}; + if (!sendto_channel(cmd->chid, &packet, TCP_MAX_WAIT_MS, TCP_MAX_RETRIES)) return_error(ERR_SERV); + return 1; +} +/// switches on command type and operates accordingly +static u64 process_cmd(enum commd_type type, struct commd *cmd, enum commd_error *NONNULL e) { + // network byte order conversion + switch (type) { + case CMD_LEAVE: + case CMD_JOIN: ((struct commd_conv *)cmd)->_3 = ntoh64(((struct commd_conv *)cmd)->_3); FALLTHROUGH; + case CMD_UNREGISTER: + case CMD_REGISTER: + case CMD_DELETE: ((struct commd_conv *)cmd)->_2 = ntoh64(((struct commd_conv *)cmd)->_2); FALLTHROUGH; + case CMD_CREATE: + case CMD_GET_PORT: ((struct commd_conv *)cmd)->_1 = ntoh64(((struct commd_conv *)cmd)->_1); FALLTHROUGH; + case CMD_GET_CHANNELS:; + } + // processing + switch (type) { + case CMD_REGISTER: return commd_register_process((struct commd_register *)cmd, e); + case CMD_UNREGISTER: return commd_unregister_process((struct commd_unregister *)cmd, e); + case CMD_CREATE: return commd_create_process((struct commd_create *)cmd, e); + case CMD_DELETE: return commd_delete_process((struct commd_delete *)cmd, e); + case CMD_JOIN: return commd_join_process((struct commd_join *)cmd, e); + case CMD_LEAVE: return commd_leave_process((struct commd_leave *)cmd, e); + case CMD_GET_PORT: return (u64)get_channel_port(((struct commd_get_port *)cmd)->cihd); + case CMD_GET_CHANNELS: return_error(ERR_DO_IT_YOURSELF); + } + return_error(ERR_PARAM); +} +static void process_connection(int sockfd) { + DEBUG("PROCESSING CONNECTION\n"); + // TODO: protection against blocking reads + enum commd_type type; + if (read(sockfd, &type, sizeof(type)) != sizeof(type)) report_error(sockfd, ERR_INVAL); + type = ntohl(type); + struct commd cmd; + memset(&cmd, 0, sizeof(cmd)); // TODO: consider to remove + i64 commd_size = commd_size_lookup[type]; + if (read(sockfd, &cmd, commd_size) != commd_size) report_error(sockfd, ERR_INVAL); + enum commd_error e = ERR_SUCCESS; + u64 cmd_status = process_cmd(type, &cmd, &e); + if (e == ERR_DO_IT_YOURSELF) cmd_status = send_channels(sockfd, &e); + cmd_status = hton64(cmd_status); + if (e != ERR_SUCCESS) report_error(sockfd, e); + write(sockfd, &cmd_status, sizeof(cmd_status)); +} + +u64 spawn_channel(struct thread_loop_arg *arg) { + pthread_t thread; + pthread_create(&thread, NULL, thread_loop, arg); + return thread; +} +bool sendto_channel(u64 chid, struct kv_system_packet *packet, int wait_ack_ms, int repeat) { + bool success = wait_ack_ms == 0; + varchnl.id = chid; + struct tcp_channel *ch = hset_at(&channels, &varchnl); + if (ch == NULL) return false; + set_sock_timeout(udpctlfd, wait_ack_ms); + + struct sockaddr_in chaddr = {0}; + socklen_t len = sizeof(chaddr); + getsockname(ch->fd, (struct sockaddr *)&chaddr, &len); + do { + sendto(udpctlfd, packet, KV_PACKET_SIZE, 0, (struct sockaddr *)&chaddr, len); + if (wait_ack_ms == 0) continue; + struct kv_system_packet resp; + recvfrom(udpctlfd, &resp, KV_PACKET_SIZE, 0, (struct sockaddr *)&chaddr, &len); + if (errno == EWOULDBLOCK || errno == EAGAIN) continue; + if (resp.operation_id == SYS_ACK) success = true; + } while (--repeat >= 0); + + return success; +} +void tcp_loop(void) { + init_statics(); + init_admin(ADMIN_UID); + int sock = setup_socket(TCP_PORT); + if (listen(sock, LISTEN_AMOUNT) != 0) { + perror("listen on TCP socket failed"); + exit(EXIT_FAILURE); + } + DEBUGF("listening on port %hu\n", TCP_PORT); + struct sockaddr_in accept_addr; + socklen_t addrlen = sizeof(accept_addr); + int currfd; + while (!should_exit) { + currfd = accept(sock, (struct sockaddr *)&accept_addr, &addrlen); + if (currfd < 0) continue; + DEBUGF("accepted connection on port %hu\n", accept_addr.sin_port); + process_connection(currfd); + shutdown(currfd, SHUT_RDWR); + close(currfd); + } + close(sock); + close(udpctlfd); + hset_free(&users); + hset_free(&channels); +} |