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+/*
+ * Ouroboros - Copyright (C) 2016 - 2026
+ *
+ * Points of attachment (PoA) - internal API
+ *
+ * Dimitri Staessens <dimitri@ouroboros.rocks>
+ * Sander Vrijders <sander@ouroboros.rocks>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#ifndef OUROBOROS_LIB_POA_POA_H
+#define OUROBOROS_LIB_POA_POA_H
+
+#include <ouroboros/atomics.h>
+#include <ouroboros/ipcp-dev.h>
+#include <ouroboros/list.h>
+#include <ouroboros/qos.h>
+#include <ouroboros/rcu.h>
+#include <ouroboros/ssm_flow_set.h>
+#include <ouroboros/ssm_pool.h>
+#include <ouroboros/ssm_rbuff.h>
+#include <ouroboros/time.h>
+#include <ouroboros/utils.h>
+
+#include <errno.h>
+#include <limits.h>
+#include <poll.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#define POA_MGMT_EID 0 /* reserved for the mgmt channel */
+
+#define POA_FLOW_REQ 1
+#define POA_FLOW_REPLY 2
+#define POA_FLOW_UPDATE 3
+#define POA_NAME_QUERY 4
+#define POA_NAME_REPLY 5
+
+#define POA_QUERY_HLEN 32 /* SHA3-256, the query hash algorithm */
+
+/* Fits "udp6.<ip6>.<port>", the longest display/RIB entry name. */
+#define POA_NAME_STRLEN 63
+
+/* Management message; every transport frames it the same way. */
+struct poa_mgmt_msg {
+ uint8_t code;
+ uint8_t resv[3];
+ uint32_t s_eid;
+ uint32_t d_eid;
+ int32_t response;
+ uint64_t bandwidth;
+ uint32_t delay;
+ uint32_t loss;
+ uint32_t ber;
+ uint32_t max_gap;
+ uint32_t timeout;
+ uint8_t availability;
+ uint8_t service;
+ uint16_t data_len;
+} __attribute__((packed));
+
+struct poa;
+struct poa_flow;
+
+#ifdef PROC_FLOW_STATS
+#define POA_STAT_BUMP(poa, field) FETCH_ADD_RELAXED(&(poa)->stat.field, 1)
+#define POA_STAT_ADD(poa, field, v) FETCH_ADD_RELAXED(&(poa)->stat.field, (v))
+#define POA_STAT_SUB(poa, field, v) FETCH_SUB_RELAXED(&(poa)->stat.field, (v))
+#define POA_STAT_LOAD(poa, field) LOAD_RELAXED(&(poa)->stat.field)
+#else
+#define POA_STAT_BUMP(poa, field) ((void) (poa))
+#define POA_STAT_ADD(poa, field, v) ((void) (poa), (void) (v))
+#define POA_STAT_SUB(poa, field, v) ((void) (poa), (void) (v))
+#define POA_STAT_LOAD(poa, field) ((void) (poa), (size_t) 0)
+#endif
+
+struct poa_stat {
+ size_t n_flows; /* gauge; the RIB reads it without poas.lock */
+ size_t rx_pkts; /* packets delivered to a flow */
+ size_t rx_bytes; /* payload bytes delivered */
+ size_t tx_pkts; /* packets handed to the transport */
+ size_t tx_bytes; /* payload bytes handed to the transport */
+ size_t mgmt_rx; /* frames queued for the mgmt handler */
+ size_t mgmt_tx; /* management frames sent */
+ size_t bad_eid; /* no flow on the EID a peer sent */
+ size_t dlv_fail; /* the rx ring above would not take it */
+ size_t buf_fail; /* no buffer to receive into */
+ size_t rcv_fail; /* transport read failed; the reader exits */
+ size_t snd_fail; /* transport send failed */
+ size_t qry_tx; /* name queries broadcast */
+ size_t qry_rx; /* name queries received */
+ size_t rep_tx; /* name replies sent, query matched */
+ size_t rep_rx; /* name replies received */
+};
+
+/* Spacing between transmit-depth samples; a depth costs a syscall. */
+#define POA_QLEN_GATE (100 * 1000) /* ns */
+
+
+/* Transport operations; public poa_X() dispatches to ops->poa_X. */
+struct poa_ops {
+ /* Parse own arm of the spec; validate; fill local and priv. */
+ int (* poa_attach)(struct poa * poa,
+ const struct poa_spec * spec);
+
+ void (* poa_detach)(struct poa * poa);
+
+ int (* poa_start)(struct poa * poa);
+
+ void (* poa_stop)(struct poa * poa);
+
+ /* Full queue: -EAGAIN unless block; then wait, to abstime if set. */
+ int (* poa_send)(struct poa * poa,
+ const struct poa_addr * dst,
+ uint32_t eid,
+ struct ssm_pk_buff * spb,
+ bool block,
+ const struct timespec * abstime);
+
+ int (* poa_send_mgmt)(struct poa * poa,
+ const struct poa_addr * dst,
+ const uint8_t * buf,
+ size_t len);
+
+ int (* poa_query)(const char * dst,
+ const struct timespec * timeo,
+ struct poa_addr * addr);
+
+ uint32_t (* poa_mtu)(struct poa * poa,
+ const struct poa_addr * dst);
+
+ /* Bytes queued in the transmit path of the PoA. */
+ size_t (* poa_qlen)(struct poa * poa);
+
+ /* Depth from the queue itself; NULL infers it from qlen. */
+ int (* poa_qpkts)(struct poa * poa,
+ size_t * pkts,
+ size_t * byts);
+
+ int (* poa_rib)(struct poa * poa,
+ char * buf,
+ size_t len);
+
+ /* Identity as a spec, e.g. for poa_list. */
+ void (* poa_spec)(const struct poa * poa,
+ struct poa_spec * spec);
+
+ /* Same identity as spec? Caller matched poa->type already. */
+ bool (* poa_has_id)(const struct poa * poa,
+ const struct poa_spec * spec);
+
+ /* Carries dst? Caller matched poa->type already. */
+ bool (* poa_match)(const struct poa * poa,
+ const struct poa_addr * dst);
+
+ /*
+ * Flows ride the link this id names; NULL: no link events.
+ * Ids are meaningful only to the backend whose monitor
+ * produced them; a single backend owns the monitor.
+ */
+ bool (* poa_link_match)(const struct poa * poa,
+ int id);
+
+ /* Maximum packet lifetime in the transport, seconds. */
+ time_t mpl;
+};
+struct poa {
+ struct list_head next;
+
+ enum poa_type type;
+ const struct poa_ops * ops;
+ void * priv;
+
+ struct poa_addr local; /* what peers dial us on */
+
+ /* Display/RIB entry name for local, e.g. "udp4.<ip>.<port>". */
+ char name[POA_NAME_STRLEN + 1];
+
+ time_t mpl;
+
+ /* Identifies the transmit queue the flows on this PoA share. */
+ int qid;
+
+ /* Mean sent packet size (bytes), EWMA over the send path. */
+ size_t avg_len;
+ /* Cost of one packet in the queue, in the transport's terms. */
+ size_t avg_ovh;
+ size_t n_tx;
+
+ /* Last queue depth read, and when, in the transport's terms. */
+ size_t q_cache;
+ uint64_t q_time;
+
+ /* Queued management frames, capped; poas.mgmt_mtx guards. */
+ size_t n_mgmt;
+
+#ifdef PROC_FLOW_STATS
+ struct poa_stat stat;
+#endif
+
+ struct bmp * eids;
+ struct poa_flow ** eid_to_pf;
+ size_t n_eids;
+
+ struct list_head flows; /* live flows, for repeats */
+
+ /* Keeps a flow and its ring alive under the receive path. */
+ struct rcu_guard guard;
+};
+
+/* poa/poa.c is part of the dev.c translation unit. */
+int poa_init(const char * name);
+
+int poa_start(void);
+
+void poa_stop(void);
+
+void poa_fini(void);
+
+/* Also answer name queries for the layer once enrolled. */
+int poa_set_layer(const char * layer);
+
+/* Hash of a name this process answers queries for? */
+bool poa_has_name(const uint8_t * hash);
+
+int poa_flow_tx(struct poa_flow * pf,
+ struct ssm_pk_buff * spb,
+ bool block,
+ const struct timespec * abstime);
+
+size_t poa_flow_qlen(const struct poa_flow * pf);
+
+size_t poa_flow_qpkts(const struct poa_flow * pf);
+
+int poa_flow_qid(const struct poa_flow * pf);
+
+size_t poa_flow_mean_len(const struct poa_flow * pf);
+
+void poa_flow_attach(struct poa_flow * pf,
+ int flow_id,
+ struct ssm_rbuff * rx_rb);
+
+void poa_flow_ready(struct poa_flow * pf);
+
+void poa_flow_detach(struct poa_flow * pf);
+
+struct poa_flow * poa_flow_take_pending(int flow_id);
+
+/* Addresses and management messages (poa/addr.c). */
+int poa_addr_cmp(const struct poa_addr * a,
+ const struct poa_addr * b);
+
+/* Display/RIB entry name, e.g. "udp4.<ip>.<port>". */
+int poa_addr_name(const struct poa_addr * a,
+ char * buf,
+ size_t len);
+
+void poa_mgmt_msg_ser(struct poa_mgmt_msg * msg,
+ uint8_t code,
+ uint32_t s_eid,
+ uint32_t d_eid,
+ qosspec_t qs,
+ int response,
+ size_t data_len);
+
+void poa_mgmt_msg_qos(const struct poa_mgmt_msg * msg,
+ qosspec_t * qs);
+
+/* Called by the transports. */
+void poa_rx_pkt(struct poa * poa,
+ uint32_t eid,
+ struct ssm_pk_buff * spb);
+
+void poa_rx_mgmt(struct poa * poa,
+ const struct poa_addr * src,
+ const uint8_t * buf,
+ size_t len);
+
+/* Reserve a buffer for a received packet, with transport headroom. */
+int poa_spb_reserve(struct ssm_pk_buff ** spb,
+ size_t len);
+
+void poa_spb_release(struct ssm_pk_buff * spb);
+
+/*
+ * All flows on PoAs whose poa_link_match reports this link id go up
+ * or down with it. Returns the number of flows whose state changed.
+ */
+size_t poa_link_updown(int id,
+ bool up);
+
+/*
+ * Link monitor: one socket for the whole subsystem, opened by
+ * poa_start(). Returns -1 where the transport has no monitor.
+ */
+int poa_monitor_open(void);
+
+/* Reads one batch of link events; cancellation point. */
+void poa_monitor_read(int fd);
+
+/* Broadcast a mgmt frame on every PoA matching dst; # sent. */
+int poa_bcast_mgmt(const struct poa_addr * dst,
+ const uint8_t * buf,
+ size_t len);
+
+/* Transport op tables. */
+extern const struct poa_ops udp_poa_ops;
+extern const struct poa_ops eth_poa_ops;
+
+/*
+ * Waits for a descriptor to take another packet, up to abstime.
+ * A NULL deadline waits indefinitely. Transports call this when
+ * their send reports the transmit queue full.
+ */
+static __inline__ int poa_wait_out(int fd,
+ const struct timespec * abstime)
+{
+ struct pollfd pfd;
+ struct timespec now;
+ long ms = -1;
+ bool clamped = false;
+ int ret;
+
+ if (abstime != NULL) {
+ clock_gettime(PTHREAD_COND_CLOCK, &now);
+
+ if (ts_diff_ns(abstime, &now) <= 0)
+ return -ETIMEDOUT;
+
+ ms = ts_diff_ms(abstime, &now) + 1; /* sub-ms must wait */
+ if (ms > INT_MAX) { /* poll takes an int */
+ ms = INT_MAX;
+ clamped = true;
+ }
+ }
+
+ pfd.fd = fd;
+ pfd.events = POLLOUT;
+ pfd.revents = 0;
+
+ ret = poll(&pfd, 1, (int) ms);
+ if (ret < 0)
+ return errno == EINTR ? 0 : -EIO;
+
+ if (ret == 0)
+ return clamped ? 0 : -ETIMEDOUT; /* clamped: retry */
+
+ return 0;
+}
+
+#endif /* OUROBOROS_LIB_POA_POA_H */
generated by cgit v1.2.3 (git 2.39.1) at 2026-09-01 11:05:20 +0000