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send DHCPv6 lease events over U-Bus #369

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12 changes: 11 additions & 1 deletion src/dhcpv6-ia.c
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Original file line number Diff line number Diff line change
Expand Up @@ -208,7 +208,7 @@ static void dhcpv6_ia_free_assignment(struct dhcp_assignment *a)
close(a->managed_sock.fd.fd);
}

if ((a->flags & OAF_BOUND) && (a->flags & OAF_DHCPV6_PD))
if (a->flags & OAF_BOUND)
apply_lease(a, false);

if (a->fr_cnt)
Expand Down Expand Up @@ -591,6 +591,10 @@ void dhcpv6_ia_write_statefile(void)
static void __apply_lease(struct dhcp_assignment *a,
struct odhcpd_ipaddr *addrs, ssize_t addr_len, bool add)
{
#ifdef WITH_UBUS
ubus_bcast_dhcp6_event(add ? "dhcpv6.ack" : "dhcpv6.release", a, addr_len, addrs);
#endif

if (a->flags & OAF_DHCPV6_NA)
return;

Expand Down Expand Up @@ -844,6 +848,9 @@ static bool assign_na(struct interface *iface, struct dhcp_assignment *a)
list_for_each_entry(c, &iface->ia_assignments, head) {
if (!(c->flags & OAF_DHCPV6_NA) || c->assigned_host_id > a->assigned_host_id ) {
list_add_tail(&a->head, &c->head);
if (a->flags &OAF_BOUND)
apply_lease(a, true);
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@kempniu kempniu Apr 1, 2026

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apply_lease() is currently used for installing routes to prefixes delegated to DHCPv6-PD clients. (Ab)using it for sending ubus notifications for address leases not only hurts readability, but it is also a very slippery slope - and it already shows.

For lease renewals, this PR causes an erroneous dhcpv6.release notification to be emitted just before a dhcpv6.ack one for the same lease. Why? assign_na() is called from dhcpv6_ia_handle_IAs(), shortly after apply_lease(a, false); is called on line 1522. Note that no release actually happens from lease management perspective; this behavior is just an artifact of emitting notifications from __apply_lease().

Please see #393 for what I hope is a more maintainable counterproposal.


return true;
} else if (c->assigned_host_id == a->assigned_host_id)
return false;
Expand Down Expand Up @@ -891,6 +898,9 @@ static bool assign_na(struct interface *iface, struct dhcp_assignment *a)
if (!(c->flags & OAF_DHCPV6_NA) || c->assigned_host_id > try) {
a->assigned_host_id = try;
list_add_tail(&a->head, &c->head);
if (a->flags &OAF_BOUND)
apply_lease(a, true);

return true;
} else if (c->assigned_host_id == try)
break;
Expand Down
6 changes: 6 additions & 0 deletions src/odhcpd.h
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Original file line number Diff line number Diff line change
Expand Up @@ -510,6 +510,12 @@ void ubus_apply_network(void);
bool ubus_has_prefix(const char *name, const char *ifname);
void ubus_bcast_dhcp_event(const char *type, const uint8_t *mac, const size_t mac_len,
const struct in_addr *addr, const char *name, const char *interface);
void ubus_bcast_dhcp6_event(
const char* type,
const struct dhcp_assignment *assignment,
size_t addrs_len,
const struct odhcpd_ipaddr addrs[static addrs_len]
);
#endif

ssize_t dhcpv6_ia_handle_IAs(uint8_t *buf, size_t buflen, struct interface *iface,
Expand Down
85 changes: 85 additions & 0 deletions src/ubus.c
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Original file line number Diff line number Diff line change
@@ -1,3 +1,4 @@
#include <stdint.h>
#include <syslog.h>
#include <libubus.h>
#include <libubox/uloop.h>
Expand All @@ -6,7 +7,9 @@
#include <inttypes.h>

#include <libubox/utils.h>
#include <time.h>

#include "libubox/blobmsg.h"
#include "odhcpd.h"
#include "dhcpv6.h"
#include "dhcpv4.h"
Expand Down Expand Up @@ -416,6 +419,88 @@ void ubus_bcast_dhcp_event(const char *type, const uint8_t *mac,
ubus_notify(ubus, &main_object, type, b.head, -1);
}

void ubus_bcast_dhcp6_event(
const char* type,
const struct dhcp_assignment *assignment,
size_t addrs_len_,
const struct odhcpd_ipaddr addrs[static addrs_len_]
) {
if (type == NULL || assignment == NULL || (addrs_len_ != 0 && addrs == NULL) || addrs_len_ > PTRDIFF_MAX)
return;

ptrdiff_t addrs_len = addrs_len_;

if (ubus == NULL || !main_object.has_subscribers)
return;

blob_buf_init(&b, 0);
if (assignment->hostname != NULL)
blobmsg_add_string(&b, "hostname", assignment->hostname);

if (assignment->iface != NULL && assignment->iface->ifname != NULL)
blobmsg_add_string(&b, "interface", assignment->iface->ifname);

if (assignment->iaid != 0)
blobmsg_add_u32(&b, "iaid", ntohl(assignment->iaid));

if (assignment->clid_len != 0) {
char *duid_buf = blobmsg_alloc_string_buffer(&b, "duid", assignment->clid_len * 2 + 1);
odhcpd_hexlify(duid_buf, assignment->clid_data, assignment->clid_len);
blobmsg_add_string_buffer(&b);
}

blobmsg_add_u8(&b, "accept-reconf", assignment->accept_fr_nonce);
blobmsg_add_u64(&b, "valid-until", assignment->valid_until);
blobmsg_add_u64(&b, "preferred-until", assignment->preferred_until);

if (assignment->flags & OAF_DHCPV6_NA)
blobmsg_add_u64(&b, "assigned", assignment->assigned_host_id);
else
blobmsg_add_u16(&b, "assigned", assignment->assigned_subnet_id);

{
void *array_h = blobmsg_open_array(&b, "flags");
if (assignment->flags & OAF_BOUND)
blobmsg_add_string(&b, NULL, "bound");

if (assignment->flags & OAF_STATIC)
blobmsg_add_string(&b, NULL, "static");

blobmsg_close_array(&b, array_h);
}

void *array_h = blobmsg_open_array(&b, assignment->flags & OAF_DHCPV6_NA ? "ipv6-addr" : "ipv6-prefix");
for (ptrdiff_t ix = 0; ix != addrs_len; ++ix) {
const struct odhcpd_ipaddr *entry = &addrs[ix];

void *table_h = blobmsg_open_table(&b, NULL);

struct in6_addr prefix = entry->addr.in6;
if (assignment->flags & OAF_DHCPV6_NA) {
prefix.s6_addr32[2] = htonl(assignment->assigned_host_id >> 32);
prefix.s6_addr32[3] = htonl(assignment->assigned_host_id & UINT32_MAX);
} else {
prefix.s6_addr32[1] |= htonl(assignment->assigned_subnet_id);
prefix.s6_addr32[2] = 0;
prefix.s6_addr32[3] = 0;
}

char *addr_buf = blobmsg_alloc_string_buffer(&b, "address", INET6_ADDRSTRLEN);
memset(addr_buf, 0, INET6_ADDRSTRLEN);

(void) inet_ntop(AF_INET6, &prefix, addr_buf, INET6_ADDRSTRLEN);
blobmsg_add_string_buffer(&b);

if (entry->prefix != 128)
blobmsg_add_u8(&b, "prefix-length", entry->prefix);

blobmsg_close_table(&b, table_h);
}

blobmsg_close_array(&b, array_h);
ubus_notify(ubus, &main_object, type, b.head, -1);
}

static void handle_event(_unused struct ubus_context *ctx, _unused struct ubus_event_handler *ev,
_unused const char *type, struct blob_attr *msg)
{
Expand Down