dhcpv6_opt() and its callers are refactored for iov_tail option parsing,
replacing direct offset management for improved robustness.
Its signature is now `bool dhcpv6_opt(iov_tail *data, type)`. `*data` (in/out)
points to a found option on `true` return or is restored on `false`.
The main dhcpv6() function uses IOV_REMOVE_HEADER for the msg_hdr, then
passes the iov_tail (now at options start) to the new dhcpv6_opt().
Signed-off-by: Laurent Vivier
Reviewed-by: David Gibson
---
dhcpv6.c | 179 ++++++++++++++++++++++++++++++++-----------------------
iov.c | 1 -
2 files changed, 104 insertions(+), 76 deletions(-)
diff --git a/dhcpv6.c b/dhcpv6.c
index ae06e646f92f..b94c8bc84b28 100644
--- a/dhcpv6.c
+++ b/dhcpv6.c
@@ -280,112 +280,125 @@ static struct resp_not_on_link_t {
/**
* dhcpv6_opt() - Get option from DHCPv6 message
- * @p: Packet pool, single packet with UDP header
- * @offset: Offset to look at, 0: end of header, set to option start
+ * @data: Buffer with options, set to matching option on return
* @type: Option type to look up, network order
*
- * Return: pointer to option header, or NULL on malformed or missing option
+ * Return: true if found and @data points to the option header,
+ * or false on malformed or missing option and @data is
+ * unmodified.
*/
-static struct opt_hdr *dhcpv6_opt(const struct pool *p, size_t *offset,
- uint16_t type)
+static bool dhcpv6_opt(struct iov_tail *data, uint16_t type)
{
- struct opt_hdr *o;
- size_t left;
+ struct iov_tail head = *data;
+ struct opt_hdr o_storage;
+ const struct opt_hdr *o;
- ASSERT(*offset >= UDP_MSG_HDR_SIZE);
-
- while ((o = packet_get_try(p, 0, *offset, sizeof(*o), &left))) {
+ while ((o = IOV_PEEK_HEADER(data, o_storage))) {
unsigned int opt_len = ntohs(o->l) + sizeof(*o);
- if (ntohs(o->l) > left)
- return NULL;
+ if (opt_len > iov_tail_size(data))
+ break;
if (o->t == type)
- return o;
+ return true;
- *offset += opt_len;
+ iov_drop_header(data, opt_len);
}
- return NULL;
+ *data = head;
+ return false;
}
/**
* dhcpv6_ia_notonlink() - Check if any IA contains non-appropriate addresses
- * @p: Packet pool, single packet starting from UDP header
+ * @data: Data to look at, packet starting from UDP header (input/output)
* @la: Address we want to lease to the client
*
- * Return: pointer to non-appropriate IA_NA or IA_TA, if any, NULL otherwise
+ * Return: true and @data points to non-appropriate IA_NA or IA_TA, if any,
+ * false otherwise and @data is unmodified
*/
-static struct opt_hdr *dhcpv6_ia_notonlink(const struct pool *p,
- struct in6_addr *la)
+static bool dhcpv6_ia_notonlink(struct iov_tail *data,
+ struct in6_addr *la)
{
int ia_types[2] = { OPT_IA_NA, OPT_IA_TA }, *ia_type;
+ struct opt_ia_addr opt_addr_storage;
const struct opt_ia_addr *opt_addr;
+ struct iov_tail current, ia_base;
+ struct opt_ia_na ia_storage;
char buf[INET6_ADDRSTRLEN];
+ const struct opt_ia_na *ia;
struct in6_addr req_addr;
+ struct opt_hdr h_storage;
const struct opt_hdr *h;
- struct opt_hdr *ia;
- size_t offset;
foreach(ia_type, ia_types) {
- offset = UDP_MSG_HDR_SIZE;
- while ((ia = dhcpv6_opt(p, &offset, *ia_type))) {
- if (ntohs(ia->l) < OPT_VSIZE(ia_na))
- return NULL;
-
- offset += sizeof(struct opt_ia_na);
+ current = *data;
+ while (dhcpv6_opt(¤t, *ia_type)) {
+ ia_base = current;
+ ia = IOV_REMOVE_HEADER(¤t, ia_storage);
+ if (!ia || ntohs(ia->hdr.l) < OPT_VSIZE(ia_na))
+ goto notfound;
+
+ while (dhcpv6_opt(¤t, OPT_IAAADR)) {
+ h = IOV_PEEK_HEADER(¤t, h_storage);
+ if (!h || ntohs(h->l) != OPT_VSIZE(ia_addr))
+ goto notfound;
+
+ opt_addr = IOV_REMOVE_HEADER(¤t,
+ opt_addr_storage);
+ if (!opt_addr)
+ goto notfound;
- while ((h = dhcpv6_opt(p, &offset, OPT_IAAADR))) {
- 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;
-
- offset += sizeof(struct opt_ia_addr);
+ goto notonlink;
}
}
}
- return NULL;
+notfound:
+ return false;
-err:
+notonlink:
info("DHCPv6: requested address %s not on link",
inet_ntop(AF_INET6, &req_addr, buf, sizeof(buf)));
- return ia;
+ *data = ia_base;
+ return true;
}
/**
* dhcpv6_send_ia_notonlink() - Send NotOnLink status
- * @c: Execution context
- * @ia: Pointer to non-appropriate IA_NA or IA_TA
- * @client_id: Client ID message option
- * xid: Transaction ID for message exchange
+ * @c: Execution context
+ * @ia_base: Non-appropriate IA_NA or IA_TA base
+ * @client_id_base: Client ID message option base
+ * @len: Client ID length
+ * @xid: Transaction ID for message exchange
*/
-static void dhcpv6_send_ia_notonlink(struct ctx *c, struct opt_hdr *ia,
- const struct opt_hdr *client_id,
- uint32_t xid)
+static void dhcpv6_send_ia_notonlink(struct ctx *c,
+ const struct iov_tail *ia_base,
+ const struct iov_tail *client_id_base,
+ int len, uint32_t xid)
{
const struct in6_addr *src = &c->ip6.our_tap_ll;
+ struct opt_hdr *ia = (struct opt_hdr *)resp_not_on_link.var;
size_t n;
info("DHCPv6: received CONFIRM with inappropriate IA,"
" sending NotOnLink status in REPLY");
- ia->l = htons(OPT_VSIZE(ia_na) + sizeof(sc_not_on_link));
-
n = sizeof(struct opt_ia_na);
- memcpy(resp_not_on_link.var, ia, n);
+ iov_to_buf(&ia_base->iov[0], ia_base->cnt, ia_base->off,
+ resp_not_on_link.var, n);
+ ia->l = htons(OPT_VSIZE(ia_na) + sizeof(sc_not_on_link));
memcpy(resp_not_on_link.var + n, &sc_not_on_link,
sizeof(sc_not_on_link));
n += sizeof(sc_not_on_link);
- memcpy(resp_not_on_link.var + n, client_id,
- sizeof(struct opt_hdr) + ntohs(client_id->l));
+ iov_to_buf(&client_id_base->iov[0], client_id_base->cnt,
+ client_id_base->off, resp_not_on_link.var + n,
+ sizeof(struct opt_hdr) + len);
- n += sizeof(struct opt_hdr) + ntohs(client_id->l);
+ n += sizeof(struct opt_hdr) + len;
n = offsetof(struct resp_not_on_link_t, var) + n;
@@ -474,17 +487,19 @@ search:
/**
* dhcpv6_client_fqdn_fill() - Fill in client FQDN option
+ * @data: Data to look at
* @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,
+static size_t dhcpv6_client_fqdn_fill(const struct iov_tail *data,
+ const struct ctx *c,
char *buf, int offset)
{
- struct opt_client_fqdn const *req_opt;
+ struct iov_tail current = *data;
struct opt_client_fqdn *o;
size_t opt_len;
@@ -502,14 +517,16 @@ static size_t dhcpv6_client_fqdn_fill(const struct pool *p, const struct ctx *c,
}
o = (struct opt_client_fqdn *)(buf + offset);
+ o->flags = 0x00;
encode_domain_name(o->domain_name, c->fqdn);
- req_opt = (struct opt_client_fqdn *)dhcpv6_opt(p,
- &(size_t){ UDP_MSG_HDR_SIZE },
- OPT_CLIENT_FQDN);
- if (req_opt && req_opt->flags & 0x01 /* S flag */)
- o->flags = 0x02 /* O flag */;
- else
- o->flags = 0x00;
+ if (dhcpv6_opt(¤t, OPT_CLIENT_FQDN)) {
+ struct opt_client_fqdn req_opt_storage;
+ struct opt_client_fqdn const *req_opt;
+
+ req_opt = IOV_PEEK_HEADER(¤t, req_opt_storage);
+ if (req_opt && req_opt->flags & 0x01 /* S flag */)
+ o->flags = 0x02 /* O flag */;
+ }
opt_len++;
@@ -531,14 +548,18 @@ static size_t dhcpv6_client_fqdn_fill(const struct pool *p, const struct ctx *c,
int dhcpv6(struct ctx *c, const struct pool *p,
const struct in6_addr *saddr, const struct in6_addr *daddr)
{
- const struct opt_hdr *client_id, *server_id, *ia;
+ const struct opt_server_id *server_id = NULL;
+ struct iov_tail data, opt, client_id_base;
+ const struct opt_hdr *client_id = NULL;
+ struct opt_server_id server_id_storage;
+ const struct opt_ia_na *ia = NULL;
+ struct opt_hdr client_id_storage;
+ struct opt_ia_na ia_storage;
const struct in6_addr *src;
struct msg_hdr mh_storage;
const struct msg_hdr *mh;
struct udphdr uh_storage;
const struct udphdr *uh;
- struct opt_hdr *bad_ia;
- struct iov_tail data;
size_t mlen, n;
if (!packet_data(p, 0, &data))
@@ -565,20 +586,26 @@ int dhcpv6(struct ctx *c, const struct pool *p,
src = &c->ip6.our_tap_ll;
- mh = IOV_PEEK_HEADER(&data, mh_storage);
+ mh = IOV_REMOVE_HEADER(&data, mh_storage);
if (!mh)
return -1;
- client_id = dhcpv6_opt(p, &(size_t){ UDP_MSG_HDR_SIZE }, OPT_CLIENTID);
+ client_id_base = data;
+ if (dhcpv6_opt(&client_id_base, OPT_CLIENTID))
+ client_id = IOV_PEEK_HEADER(&client_id_base, client_id_storage);
if (!client_id || ntohs(client_id->l) > OPT_VSIZE(client_id))
return -1;
- server_id = dhcpv6_opt(p, &(size_t){ UDP_MSG_HDR_SIZE }, OPT_SERVERID);
- if (server_id && ntohs(server_id->l) != OPT_VSIZE(server_id))
+ opt = data;
+ if (dhcpv6_opt(&opt, OPT_SERVERID))
+ server_id = IOV_PEEK_HEADER(&opt, server_id_storage);
+ if (server_id && ntohs(server_id->hdr.l) != OPT_VSIZE(server_id))
return -1;
- ia = dhcpv6_opt(p, &(size_t){ UDP_MSG_HDR_SIZE }, OPT_IA_NA);
- if (ia && ntohs(ia->l) < MIN(OPT_VSIZE(ia_na), OPT_VSIZE(ia_ta)))
+ opt = data;
+ if (dhcpv6_opt(&opt, OPT_IA_NA))
+ ia = IOV_PEEK_HEADER(&opt, ia_storage);
+ if (ia && ntohs(ia->hdr.l) < MIN(OPT_VSIZE(ia_na), OPT_VSIZE(ia_ta)))
return -1;
resp.hdr.type = TYPE_REPLY;
@@ -593,9 +620,10 @@ int dhcpv6(struct ctx *c, const struct pool *p,
if (mh->type == TYPE_CONFIRM && server_id)
return -1;
- if ((bad_ia = dhcpv6_ia_notonlink(p, &c->ip6.addr))) {
+ if (dhcpv6_ia_notonlink(&data, &c->ip6.addr)) {
- dhcpv6_send_ia_notonlink(c, bad_ia, client_id, mh->xid);
+ dhcpv6_send_ia_notonlink(c, &data, &client_id_base,
+ ntohs(client_id->l), mh->xid);
return 1;
}
@@ -607,7 +635,7 @@ int dhcpv6(struct ctx *c, const struct pool *p,
memcmp(&resp.server_id, server_id, sizeof(resp.server_id)))
return -1;
- if (ia || dhcpv6_opt(p, &(size_t){ UDP_MSG_HDR_SIZE }, OPT_IA_TA))
+ if (ia || dhcpv6_opt(&data, OPT_IA_TA))
return -1;
info("DHCPv6: received INFORMATION_REQUEST, sending REPLY");
@@ -633,13 +661,14 @@ int dhcpv6(struct ctx *c, const struct pool *p,
if (ia)
resp.ia_na.iaid = ((struct opt_ia_na *)ia)->iaid;
- memcpy(&resp.client_id, client_id,
- ntohs(client_id->l) + sizeof(struct opt_hdr));
+ iov_to_buf(&client_id_base.iov[0], client_id_base.cnt,
+ client_id_base.off, &resp.client_id,
+ ntohs(client_id->l) + sizeof(struct opt_hdr));
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);
+ n = dhcpv6_client_fqdn_fill(&data, c, (char *)&resp, n);
resp.hdr.xid = mh->xid;
diff --git a/iov.c b/iov.c
index 35dc60380c8c..8c74a59b8e96 100644
--- a/iov.c
+++ b/iov.c
@@ -109,7 +109,6 @@ size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt,
*
* Return: the number of bytes successfully copied.
*/
-/* cppcheck-suppress [staticFunction] */
size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt,
size_t offset, void *buf, size_t bytes)
{
--
2.50.1