lib: Replace shim IPCPs with points of attachment

Removes the UDP and Ethernet shim IPCPs. The unicast and broadcast
IPCPs can now directly attach to a "legacy" socket. We adopt Saltzer's
Point-of-Attachment terminology, also advocated in Day's "Patterns in
Network Architecture". The "poa" component manages these
PoA's with one management thread, one link monitoring thread and one
thread per attached point.

For Ethernet PoA's the irm connect and enroll can resolve the
destination IPCP or Layer name with a broadcast name query over the
attached PoAs (first reply wins). UDP PoA's require a destination IP
address or FQDN.

attach to a local endpoint (required both server and client side):

 irm ipcp poa attach name a udp 10.0.0.1
 irm ipcp poa attach name a udp 10.0.0.1:3435
 irm ipcp poa attach name a udp [::1]:3435
 irm ipcp poa attach name a eth dev eth0
 irm ipcp poa attach name a eth dev eth0 ethertype 0xA000

release a PoA (refused while it carries a flow):

 irm ipcp poa detach name a udp 10.0.0.1:3435
 irm ipcp poa detach name a eth eth0

list an IPCP's PoAs:

 irm ipcp poa list name a

connect to a peer, by name or at an address:

 irm ipcp connect name b dst a
 irm ipcp connect name b dst a eth
 irm ipcp connect name b dst a eth dev eth0
 irm ipcp connect name b dst a udp 10.0.0.1:3435
 irm ipcp connect name b dst a udp peer.example.com:3435

disconnect by peer name, no address:

 irm ipcp disconnect name b dst a
 irm ipcp disconnect name b dst a component mgmt

enroll has the same shape as connect:

 irm ipcp enroll name b layer lr autobind
 irm ipcp enroll name b layer lr autobind eth dev eth0
 irm ipcp enroll name b layer lr autobind udp 10.0.0.1:3435

the IRMd config file attaches PoAs and names peers the same way:

 udp = [ "10.0.0.1", "10.0.0.1:3436" ]
 eth = [ "eth0", {dev="eth1", ethertype=0xA007} ]

 enrol={dst="LAN", eth={dev="eth0"}}
 conn=[{dst="lan3", eth={}}, {dst="lan4", udp="10.0.0.1:3435"}]

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 142 insertions, 0 deletions

diff --git a/src/lib/poa/addr.c b/src/lib/poa/addr.c
new file mode 100644
index 00000000..d8811244
--- /dev/null
+++ b/src/lib/poa/addr.c
@@ -0,0 +1,142 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2026
+ *
+ * Points of attachment (PoA) - addresses and management messages
+ *
+ *    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/.
+ */
+
+#if defined(__linux__) || defined(__CYGWIN__)
+#ifndef _DEFAULT_SOURCE /* Test include source */
+#define _DEFAULT_SOURCE
+#endif
+#endif
+
+#include "config.h"
+
+#include <ouroboros/endian.h>
+#include <ouroboros/errno.h>
+
+#include "poa.h"
+
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <string.h>
+
+int poa_addr_cmp(const struct poa_addr * a,
+                 const struct poa_addr * b)
+{
+        if (a->type != b->type)
+                return 1;
+
+        switch (a->type) {
+        case POA_UDP4:
+                if (a->udp4.port != b->udp4.port)
+                        return 1;
+                return memcmp(&a->udp4.ip_addr, &b->udp4.ip_addr,
+                              sizeof(a->udp4.ip_addr));
+        case POA_UDP6:
+                if (a->udp6.port != b->udp6.port)
+                        return 1;
+                return memcmp(&a->udp6.ip_addr, &b->udp6.ip_addr,
+                              sizeof(a->udp6.ip_addr));
+        case POA_ETH:
+                if (a->eth.dst.ethertype != b->eth.dst.ethertype)
+                        return 1;
+                return memcmp(a->eth.dst.mac, b->eth.dst.mac, POA_MAC_SIZE);
+        default:
+                return 1;
+        }
+}
+
+/* Display/RIB entry name, e.g. "udp4.<ip>.<port>". */
+int poa_addr_name(const struct poa_addr * a,
+                  char *                  buf,
+                  size_t                  len)
+{
+        char ip[INET6_ADDRSTRLEN];
+        int  ret;
+
+        switch (a->type) {
+        case POA_UDP4:
+                if (inet_ntop(AF_INET, &a->udp4.ip_addr,
+                              ip, sizeof(ip)) == NULL)
+                        return -EINVAL;
+                ret = snprintf(buf, len, "udp4.%s.%u", ip, a->udp4.port);
+                break;
+        case POA_UDP6:
+                if (inet_ntop(AF_INET6, &a->udp6.ip_addr,
+                              ip, sizeof(ip)) == NULL)
+                        return -EINVAL;
+                ret = snprintf(buf, len, "udp6.%s.%u", ip, a->udp6.port);
+                break;
+        case POA_ETH:
+                ret = snprintf(buf, len, "eth.%s.%04X",
+                               a->eth.src.dev, a->eth.src.ethertype);
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        if (ret < 0 || (size_t) ret >= len)
+                return -EMSGSIZE;
+
+        return 0;
+}
+
+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)
+{
+        memset(msg, 0, sizeof(*msg));
+
+        msg->code         = code;
+        msg->s_eid        = hton32(s_eid);
+        msg->d_eid        = hton32(d_eid);
+        msg->response     = hton32(response);
+        msg->data_len     = hton16((uint16_t) data_len);
+
+        if (code != POA_FLOW_REQ)
+                return;
+
+        msg->bandwidth    = hton64(qs.bandwidth);
+        msg->delay        = hton32(qs.delay);
+        msg->loss         = hton32(qs.loss);
+        msg->ber          = hton32(qs.ber);
+        msg->max_gap      = hton32(qs.max_gap);
+        msg->timeout      = hton32(qs.timeout);
+        msg->availability = qs.availability;
+        msg->service      = qs.service;
+}
+
+void poa_mgmt_msg_qos(const struct poa_mgmt_msg * msg,
+                      qosspec_t *                 qs)
+{
+        qs->bandwidth    = ntoh64(msg->bandwidth);
+        qs->delay        = ntoh32(msg->delay);
+        qs->loss         = ntoh32(msg->loss);
+        qs->ber          = ntoh32(msg->ber);
+        qs->max_gap      = ntoh32(msg->max_gap);
+        qs->timeout      = ntoh32(msg->timeout);
+        qs->availability = msg->availability;
+        qs->service      = msg->service;
+}
+