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path: root/dhcpv6.c
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Diffstat (limited to 'dhcpv6.c')
-rw-r--r--dhcpv6.c169
1 files changed, 118 insertions, 51 deletions
diff --git a/dhcpv6.c b/dhcpv6.c
index 7dcca2a..ba16c66 100644
--- a/dhcpv6.c
+++ b/dhcpv6.c
@@ -48,6 +48,7 @@ struct opt_hdr {
# define STATUS_NOTONLINK htons_constant(4)
# define OPT_DNS_SERVERS htons_constant(23)
# define OPT_DNS_SEARCH htons_constant(24)
+# define OPT_CLIENT_FQDN htons_constant(39)
#define STR_NOTONLINK "Prefix not appropriate for link."
uint16_t l;
@@ -58,6 +59,9 @@ struct opt_hdr {
sizeof(struct opt_hdr))
#define OPT_VSIZE(x) (sizeof(struct opt_##x) - \
sizeof(struct opt_hdr))
+#define OPT_MAX_SIZE IPV6_MIN_MTU - (sizeof(struct ipv6hdr) + \
+ sizeof(struct udphdr) + \
+ sizeof(struct msg_hdr))
/**
* struct opt_client_id - DHCPv6 Client Identifier option
@@ -140,7 +144,9 @@ struct opt_ia_addr {
struct opt_status_code {
struct opt_hdr hdr;
uint16_t code;
- char status_msg[sizeof(STR_NOTONLINK) - 1];
+ /* "nonstring" is only supported since clang 23 */
+ /* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */
+ __attribute__((nonstring)) char status_msg[sizeof(STR_NOTONLINK) - 1];
} __attribute__((packed));
/**
@@ -164,6 +170,18 @@ struct opt_dns_search {
} __attribute__((packed));
/**
+ * struct opt_client_fqdn - Client FQDN option (RFC 4704)
+ * @hdr: Option header
+ * @flags: Flags described by RFC 4704
+ * @domain_name: Client FQDN
+ */
+struct opt_client_fqdn {
+ struct opt_hdr hdr;
+ uint8_t flags;
+ char domain_name[PASST_MAXDNAME];
+} __attribute__((packed));
+
+/**
* struct msg_hdr - DHCPv6 client/server message header
* @type: DHCP message type
* @xid: Transaction ID for message exchange
@@ -193,6 +211,7 @@ struct msg_hdr {
* @client_id: Client Identifier, variable length
* @dns_servers: DNS Recursive Name Server, here just for storage size
* @dns_search: Domain Search List, here just for storage size
+ * @client_fqdn: Client FQDN, variable length
*/
static struct resp_t {
struct msg_hdr hdr;
@@ -203,6 +222,7 @@ static struct resp_t {
struct opt_client_id client_id;
struct opt_dns_servers dns_servers;
struct opt_dns_search dns_search;
+ struct opt_client_fqdn client_fqdn;
} __attribute__((__packed__)) resp = {
{ 0 },
SERVER_ID,
@@ -228,6 +248,10 @@ static struct resp_t {
{ { OPT_DNS_SEARCH, 0, },
{ 0 },
},
+
+ { { OPT_CLIENT_FQDN, 0, },
+ 0, { 0 },
+ },
};
static const struct opt_status_code sc_not_on_link = {
@@ -296,45 +320,42 @@ static struct opt_hdr *dhcpv6_opt(const struct pool *p, size_t *offset,
static struct opt_hdr *dhcpv6_ia_notonlink(const struct pool *p,
struct in6_addr *la)
{
+ int ia_types[2] = { OPT_IA_NA, OPT_IA_TA }, *ia_type;
+ const struct opt_ia_addr *opt_addr;
char buf[INET6_ADDRSTRLEN];
struct in6_addr req_addr;
- struct opt_hdr *ia, *h;
+ const struct opt_hdr *h;
+ struct opt_hdr *ia;
size_t offset;
- int ia_type;
- ia_type = OPT_IA_NA;
-ia_ta:
- offset = 0;
- while ((ia = dhcpv6_opt(p, &offset, ia_type))) {
- if (ntohs(ia->l) < OPT_VSIZE(ia_na))
- return NULL;
+ foreach(ia_type, ia_types) {
+ offset = 0;
+ while ((ia = dhcpv6_opt(p, &offset, *ia_type))) {
+ if (ntohs(ia->l) < OPT_VSIZE(ia_na))
+ return NULL;
- offset += sizeof(struct opt_ia_na);
+ offset += sizeof(struct opt_ia_na);
- while ((h = dhcpv6_opt(p, &offset, OPT_IAAADR))) {
- struct opt_ia_addr *opt_addr = (struct opt_ia_addr *)h;
+ while ((h = dhcpv6_opt(p, &offset, OPT_IAAADR))) {
+ if (ntohs(h->l) != OPT_VSIZE(ia_addr))
+ return NULL;
- if (ntohs(h->l) != OPT_VSIZE(ia_addr))
- return NULL;
+ opt_addr = (const struct opt_ia_addr *)h;
+ req_addr = opt_addr->addr;
+ if (!IN6_ARE_ADDR_EQUAL(la, &req_addr))
+ goto err;
- memcpy(&req_addr, &opt_addr->addr, sizeof(req_addr));
- if (!IN6_ARE_ADDR_EQUAL(la, &req_addr)) {
- info("DHCPv6: requested address %s not on link",
- inet_ntop(AF_INET6, &req_addr,
- buf, sizeof(buf)));
- return ia;
+ offset += sizeof(struct opt_ia_addr);
}
-
- offset += sizeof(struct opt_ia_addr);
}
}
- if (ia_type == OPT_IA_NA) {
- ia_type = OPT_IA_TA;
- goto ia_ta;
- }
-
return NULL;
+
+err:
+ info("DHCPv6: requested address %s not on link",
+ inet_ntop(AF_INET6, &req_addr, buf, sizeof(buf)));
+ return ia;
}
/**
@@ -349,7 +370,6 @@ static size_t dhcpv6_dns_fill(const struct ctx *c, char *buf, int offset)
{
struct opt_dns_servers *srv = NULL;
struct opt_dns_search *srch = NULL;
- char *p = NULL;
int i;
if (c->no_dhcp_dns)
@@ -363,7 +383,7 @@ static size_t dhcpv6_dns_fill(const struct ctx *c, char *buf, int offset)
srv->hdr.l = 0;
}
- memcpy(&srv->addr[i], &c->ip6.dns[i], sizeof(srv->addr[i]));
+ srv->addr[i] = c->ip6.dns[i];
srv->hdr.l += sizeof(srv->addr[i]);
offset += sizeof(srv->addr[i]);
}
@@ -386,35 +406,82 @@ search:
if (!name_len)
continue;
+ name_len += 2; /* Length byte for first label, and terminator */
+ if (name_len >
+ NS_MAXDNAME + 1 /* Length byte for first label */ ||
+ name_len > 255) {
+ debug("DHCP: DNS search name '%s' too long, skipping",
+ c->dns_search[i].n);
+ continue;
+ }
+
if (!srch) {
srch = (struct opt_dns_search *)(buf + offset);
offset += sizeof(struct opt_hdr);
srch->hdr.t = OPT_DNS_SEARCH;
srch->hdr.l = 0;
- p = srch->list;
}
- *p = '.';
- p = stpncpy(p + 1, c->dns_search[i].n, name_len);
- p++;
- srch->hdr.l += name_len + 2;
- offset += name_len + 2;
+ encode_domain_name(buf + offset, c->dns_search[i].n);
+
+ srch->hdr.l += name_len;
+ offset += name_len;
+
}
- if (srch) {
- for (i = 0; i < srch->hdr.l; i++) {
- if (srch->list[i] == '.') {
- srch->list[i] = strcspn(srch->list + i + 1,
- ".");
- }
- }
+ if (srch)
srch->hdr.l = htons(srch->hdr.l);
- }
return offset;
}
/**
+ * dhcpv6_client_fqdn_fill() - Fill in client FQDN option
+ * @c: Execution context
+ * @buf: Response message buffer where options will be appended
+ * @offset: Offset in message buffer for new options
+ *
+ * Return: updated length of response message buffer.
+ */
+static size_t dhcpv6_client_fqdn_fill(const struct pool *p, const struct ctx *c,
+ char *buf, int offset)
+
+{
+ struct opt_client_fqdn const *req_opt;
+ struct opt_client_fqdn *o;
+ size_t opt_len;
+
+ opt_len = strlen(c->fqdn);
+ if (opt_len == 0) {
+ return offset;
+ }
+
+ opt_len += 2; /* Length byte for first label, and terminator */
+ if (opt_len > OPT_MAX_SIZE - (offset +
+ sizeof(struct opt_hdr) +
+ 1 /* flags */ )) {
+ debug("DHCPv6: client FQDN option doesn't fit, skipping");
+ return offset;
+ }
+
+ o = (struct opt_client_fqdn *)(buf + offset);
+ encode_domain_name(o->domain_name, c->fqdn);
+ req_opt = (struct opt_client_fqdn *)dhcpv6_opt(p, &(size_t){ 0 },
+ OPT_CLIENT_FQDN);
+ if (req_opt && req_opt->flags & 0x01 /* S flag */)
+ o->flags = 0x02 /* O flag */;
+ else
+ o->flags = 0x00;
+
+ opt_len++;
+
+ o->hdr.t = OPT_CLIENT_FQDN;
+ o->hdr.l = htons(opt_len);
+
+ return offset + sizeof(struct opt_hdr) + opt_len;
+}
+
+/**
* dhcpv6() - Check if this is a DHCPv6 message, reply as needed
* @c: Execution context
* @p: Packet pool, single packet starting from UDP header
@@ -426,11 +493,11 @@ search:
int dhcpv6(struct ctx *c, const struct pool *p,
const struct in6_addr *saddr, const struct in6_addr *daddr)
{
- struct opt_hdr *ia, *bad_ia, *client_id;
- const struct opt_hdr *server_id;
+ const struct opt_hdr *client_id, *server_id, *ia;
const struct in6_addr *src;
const struct msg_hdr *mh;
const struct udphdr *uh;
+ struct opt_hdr *bad_ia;
size_t mlen, n;
uh = packet_get(p, 0, 0, sizeof(*uh), &mlen);
@@ -451,10 +518,7 @@ int dhcpv6(struct ctx *c, const struct pool *p,
c->ip6.addr_ll_seen = *saddr;
- if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
- src = &c->ip6.gw;
- else
- src = &c->ip6.addr_ll;
+ src = &c->ip6.our_tap_ll;
mh = packet_get(p, 0, sizeof(*uh), sizeof(*mh), NULL);
if (!mh)
@@ -550,6 +614,7 @@ int dhcpv6(struct ctx *c, const struct pool *p,
n = offsetof(struct resp_t, client_id) +
sizeof(struct opt_hdr) + ntohs(client_id->l);
n = dhcpv6_dns_fill(c, (char *)&resp, n);
+ n = dhcpv6_client_fqdn_fill(p, c, (char *)&resp, n);
resp.hdr.xid = mh->xid;
@@ -574,8 +639,10 @@ void dhcpv6_init(const struct ctx *c)
resp.server_id.duid_time = duid_time;
resp_not_on_link.server_id.duid_time = duid_time;
- memcpy(resp.server_id.duid_lladdr, c->mac, sizeof(c->mac));
- memcpy(resp_not_on_link.server_id.duid_lladdr, c->mac, sizeof(c->mac));
+ memcpy(resp.server_id.duid_lladdr,
+ c->our_tap_mac, sizeof(c->our_tap_mac));
+ memcpy(resp_not_on_link.server_id.duid_lladdr,
+ c->our_tap_mac, sizeof(c->our_tap_mac));
resp.ia_addr.addr = c->ip6.addr;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-04 00:48:35 +0000