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Merge pull request #15669 from andir/systemd-ipv6-pd-subnet-id

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networkd: subnet id support for ipv6 prefix delegation
This commit is contained in:
Lennart Poettering
2020-05-27 18:47:26 +02:00
committed by GitHub
parent 6bce17455e 02e9e34bd9
commit bb2294e454
11 changed files with 329 additions and 54 deletions
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src/network/networkd-dhcp6.c
+178 -38
View File
@@ -25,6 +25,7 @@ static int dhcp6_lease_address_acquired(sd_dhcp6_client *client, Link *link);
static Link *dhcp6_prefix_get(Manager *m, struct in6_addr *addr);
static int dhcp6_prefix_add(Manager *m, struct in6_addr *addr, Link *link);
static int dhcp6_prefix_remove_all(Manager *m, Link *link);
static bool dhcp6_link_has_dhcpv6_prefix(Link *link);
static bool dhcp6_get_prefix_delegation(Link *link) {
if (!link->network)
@@ -35,6 +36,97 @@ static bool dhcp6_get_prefix_delegation(Link *link) {
RADV_PREFIX_DELEGATION_BOTH);
}
static bool dhcp6_has_preferred_subnet_id(Link *link) {
if (!link->network)
return false;
return link->network->router_prefix_subnet_id >= 0;
}
static int dhcp6_get_preferred_delegated_prefix(
Manager* manager,
Link *link,
const struct in6_addr *pd_prefix,
uint8_t pd_prefix_len,
struct in6_addr *ret_addr) {
int r;
union in_addr_union pd_prefix_union = {
.in6 = *pd_prefix,
};
int64_t subnet_id = link->network->router_prefix_subnet_id;
assert(pd_prefix_len <= 64);
uint8_t prefix_bits = 64 - pd_prefix_len;
uint64_t n_prefixes = UINT64_C(1) << prefix_bits;
_cleanup_free_ char *assigned_buf = NULL;
/* We start off with the original PD prefix we have been assigned and
* iterate from there */
union in_addr_union prefix = {
.in6 = *pd_prefix,
};
if (subnet_id >= 0) {
/* If the link has a preference for a particular subnet id try to allocate that */
if ((uint64_t)subnet_id >= n_prefixes)
return log_link_debug_errno(link,
SYNTHETIC_ERRNO(ERANGE),
"subnet id %" PRIi64 " is out of range. Only have %" PRIu64 " subnets.",
subnet_id,
n_prefixes);
r = in_addr_prefix_nth(AF_INET6, &prefix, 64, subnet_id);
if (r < 0)
return log_link_debug_errno(link,
r,
"subnet id %" PRIi64 " is out of range. Only have %" PRIu64 " subnets.",
subnet_id,
n_prefixes);
/* Verify that the prefix we did calculate fits in the pd prefix.
* This should not fail as we checked the prefix size beforehand */
assert_se(in_addr_prefix_covers(AF_INET6, &pd_prefix_union, pd_prefix_len, &prefix) > 0);
Link* assigned_link = dhcp6_prefix_get(manager, &prefix.in6);
(void) in_addr_to_string(AF_INET6, &prefix, &assigned_buf);
if (assigned_link && assigned_link != link)
return log_link_error_errno(link, SYNTHETIC_ERRNO(EAGAIN),
"The requested prefix %s is already assigned to another link: %s",
strnull(assigned_buf),
strnull(assigned_link->ifname));
*ret_addr = prefix.in6;
log_link_debug(link, "The requested prefix %s is available. Using it.",
strnull(assigned_buf));
return 0;
} else {
for (uint64_t n = 0; n < n_prefixes; n++) {
/* if we do not have an allocation preference just iterate
* through the address space and return the first free prefix. */
Link* assigned_link = dhcp6_prefix_get(manager, &prefix.in6);
if (!assigned_link || assigned_link == link) {
*ret_addr = prefix.in6;
return 0;
}
r = in_addr_prefix_next(AF_INET6, &prefix, 64);
if (r < 0)
return log_link_error_errno(link,
r,
"Can't allocate another prefix. Out of address space?");
}
log_link_warning(link, "Couldn't find a suitable prefix. Ran out of address space.");
}
return -ERANGE;
}
static bool dhcp6_enable_prefix_delegation(Link *dhcp6_link) {
Manager *manager;
Link *l;
@@ -165,24 +257,27 @@ int dhcp6_lease_pd_prefix_lost(sd_dhcp6_client *client, Link* link) {
return 0;
}
static int dhcp6_pd_prefix_distribute(Link *dhcp6_link, Iterator *i,
static int dhcp6_pd_prefix_distribute(Link *dhcp6_link,
struct in6_addr *pd_prefix,
uint8_t pd_prefix_len,
uint32_t lifetime_preferred,
uint32_t lifetime_valid) {
uint32_t lifetime_valid,
bool assign_preferred_subnet_id) {
Iterator i;
Link *link;
Manager *manager = dhcp6_link->manager;
union in_addr_union prefix;
uint64_t n_prefixes, n_used = 0;
union in_addr_union prefix = {
.in6 = *pd_prefix,
};
uint64_t n_prefixes;
_cleanup_free_ char *buf = NULL;
_cleanup_free_ char *assigned_buf = NULL;
int r;
bool pool_depleted = false;
assert(manager);
assert(pd_prefix_len <= 64);
prefix.in6 = *pd_prefix;
r = in_addr_mask(AF_INET6, &prefix, pd_prefix_len);
if (r < 0)
return r;
@@ -193,15 +288,8 @@ static int dhcp6_pd_prefix_distribute(Link *dhcp6_link, Iterator *i,
log_link_debug(dhcp6_link, "Assigning up to %" PRIu64 " prefixes from %s/%u",
n_prefixes, strnull(buf), pd_prefix_len);
while (hashmap_iterate(manager->links, i, (void **)&link, NULL)) {
Link *assigned_link;
if (n_used == n_prefixes) {
log_link_debug(dhcp6_link, "Assigned %" PRIu64 "/%" PRIu64 " prefixes from %s/%u",
n_used, n_prefixes, strnull(buf), pd_prefix_len);
return -EAGAIN;
}
HASHMAP_FOREACH(link, manager->links, i) {
union in_addr_union assigned_prefix;
if (link == dhcp6_link)
continue;
@@ -209,35 +297,42 @@ static int dhcp6_pd_prefix_distribute(Link *dhcp6_link, Iterator *i,
if (!dhcp6_get_prefix_delegation(link))
continue;
assigned_link = dhcp6_prefix_get(manager, &prefix.in6);
if (assigned_link && assigned_link != link)
if (dhcp6_link_has_dhcpv6_prefix(link))
continue;
(void) in_addr_to_string(AF_INET6, &prefix, &assigned_buf);
r = dhcp6_pd_prefix_assign(link, &prefix.in6, 64,
if (assign_preferred_subnet_id != dhcp6_has_preferred_subnet_id(link))
continue;
r = dhcp6_get_preferred_delegated_prefix(manager, link, &prefix.in6, pd_prefix_len,
&assigned_prefix.in6);
if (assign_preferred_subnet_id && r == -EAGAIN) {
/* A link has a preferred subnet_id but that one is
* already taken by another link. Now all the remaining
* links will also not obtain a prefix. */
pool_depleted = true;
continue;
} else if (r < 0)
return r;
(void) in_addr_to_string(AF_INET6, &assigned_prefix, &assigned_buf);
r = dhcp6_pd_prefix_assign(link, &assigned_prefix.in6, 64,
lifetime_preferred, lifetime_valid);
if (r < 0) {
log_link_error_errno(link, r, "Unable to %s prefix %s/64 from %s/%u for link: %m",
assigned_link ? "update": "assign",
log_link_error_errno(link, r, "Unable to assign/update prefix %s/64 from %s/%u for link: %m",
strnull(assigned_buf),
strnull(buf), pd_prefix_len);
if (!assigned_link)
continue;
} else
log_link_debug(link, "Assigned prefix %" PRIu64 "/%" PRIu64 " %s/64 from %s/%u to link",
n_used + 1, n_prefixes,
log_link_debug(link, "Assigned prefix %s/64 from %s/%u to link",
strnull(assigned_buf),
strnull(buf), pd_prefix_len);
n_used++;
r = in_addr_prefix_next(AF_INET6, &prefix, 64);
if (r < 0 && n_used < n_prefixes)
return r;
}
/* If one of the link requests couldn't be fulfilled, signal that we
should try again with another prefix. */
if (pool_depleted)
return -EAGAIN;
return 0;
}
@@ -262,7 +357,6 @@ static int dhcp6_lease_pd_prefix_acquired(sd_dhcp6_client *client, Link *link) {
union in_addr_union pd_prefix;
uint8_t pd_prefix_len;
uint32_t lifetime_preferred, lifetime_valid;
Iterator i = ITERATOR_FIRST;
r = sd_dhcp6_client_get_lease(client, &lease);
if (r < 0)
@@ -314,15 +408,47 @@ static int dhcp6_lease_pd_prefix_acquired(sd_dhcp6_client *client, Link *link) {
} else
log_link_debug(link, "Not adding a blocking route since distributed prefix is /64");
r = dhcp6_pd_prefix_distribute(link, &i, &pd_prefix.in6,
/* We are doing prefix allocation in two steps:
* 1. all those links that have a preferred subnet id will be assigned their subnet
* 2. all those links that remain will receive prefixes in sequential
* order. Prefixes that were previously already allocated to another
* link will be skipped.
* If a subnet id request couldn't be fullfilled the failure will be logged (as error)
* and no further attempts at obtaining a prefix will be made.
* The assignment has to be split in two phases since subnet id
* preferences should be honored. Meaning that any subnet id should be
* handed out to the requesting link and not to some link that didn't
* specify any preference. */
r = dhcp6_pd_prefix_distribute(link, &pd_prefix.in6,
pd_prefix_len,
lifetime_preferred,
lifetime_valid);
lifetime_valid,
true);
if (r < 0 && r != -EAGAIN)
return r;
if (r >= 0)
i = ITERATOR_FIRST;
/* if r == -EAGAIN then the allocation failed because we ran
* out of addresses for the preferred subnet id's. This doesn't
* mean we can't fullfill other prefix requests.
*
* Since we do not have dedicated lists of links that request
* specific subnet id's and those that accept any prefix we
* *must* reset the iterator to the start as otherwise some
* links might not get their requested prefix. */
r = dhcp6_pd_prefix_distribute(link, &pd_prefix.in6,
pd_prefix_len,
lifetime_preferred,
lifetime_valid,
false);
if (r < 0 && r != -EAGAIN)
return r;
/* If the prefix distribution did return -EAGAIN we will try to
* fullfill those with the next available pd delegated prefix. */
}
return 0;
@@ -878,3 +1004,17 @@ static int dhcp6_prefix_remove_all(Manager *m, Link *link) {
return 0;
}
static bool dhcp6_link_has_dhcpv6_prefix(Link *link) {
Iterator i;
Link *l;
assert(link);
assert(link->manager);
HASHMAP_FOREACH(l, link->manager->dhcp6_prefixes, i)
if (link == l)
return true;
return false;
}
src/network/networkd-network-gperf.gperf
+1
View File
@@ -250,6 +250,7 @@ BridgeVLAN.PVID, config_parse_brvlan_pvid,
BridgeVLAN.VLAN, config_parse_brvlan_vlan, 0, 0
BridgeVLAN.EgressUntagged, config_parse_brvlan_untagged, 0, 0
Network.IPv6PrefixDelegation, config_parse_router_prefix_delegation, 0, 0
Network.IPv6PDSubnetId, config_parse_router_prefix_subnet_id, 0, 0
IPv6PrefixDelegation.RouterLifetimeSec, config_parse_sec, 0, offsetof(Network, router_lifetime_usec)
IPv6PrefixDelegation.Managed, config_parse_bool, 0, offsetof(Network, router_managed)
IPv6PrefixDelegation.OtherInformation, config_parse_bool, 0, offsetof(Network, router_other_information)
src/network/networkd-network.c
+1
View File
@@ -415,6 +415,7 @@ int network_load_one(Manager *manager, OrderedHashmap **networks, const char *fi
.dhcp_server_emit_router = true,
.dhcp_server_emit_timezone = true,
.router_prefix_subnet_id = -1,
.router_emit_dns = true,
.router_emit_domains = true,
src/network/networkd-network.h
+1
View File
@@ -178,6 +178,7 @@ struct Network {
/* IPv6 prefix delegation support */
RADVPrefixDelegation router_prefix_delegation;
int64_t router_prefix_subnet_id;
usec_t router_lifetime_usec;
uint8_t router_preference;
bool router_managed;
src/network/networkd-radv.c
+37
View File
@@ -864,3 +864,40 @@ int config_parse_router_preference(const char *unit,
return 0;
}
int config_parse_router_prefix_subnet_id(const char *unit,
const char *filename,
unsigned line,
const char *section,
unsigned section_line,
const char *lvalue,
int ltype,
const char *rvalue,
void *data,
void *userdata) {
Network *network = userdata;
uint64_t t;
int r;
assert(filename);
assert(lvalue);
assert(rvalue);
assert(data);
if (isempty(rvalue) || streq(rvalue, "auto")) {
network->router_prefix_subnet_id = -1;
return 0;
}
r = safe_atoux64(rvalue, &t);
if (r < 0 || t > INT64_MAX) {
log_syntax(unit, LOG_ERR, filename, line, r,
"Subnet id '%s' is invalid, ignoring assignment.",
rvalue);
return 0;
}
network->router_prefix_subnet_id = (int64_t)t;
return 0;
}
src/network/networkd-radv.h
+1
View File
@@ -58,6 +58,7 @@ RADVPrefixDelegation radv_prefix_delegation_from_string(const char *s) _pure_;
CONFIG_PARSER_PROTOTYPE(config_parse_router_prefix_delegation);
CONFIG_PARSER_PROTOTYPE(config_parse_router_preference);
CONFIG_PARSER_PROTOTYPE(config_parse_router_prefix_subnet_id);
CONFIG_PARSER_PROTOTYPE(config_parse_prefix);
CONFIG_PARSER_PROTOTYPE(config_parse_prefix_flags);
CONFIG_PARSER_PROTOTYPE(config_parse_prefix_lifetime);