We want to add support for option 80 (Rapid Commit, RFC 4039), whose
length is 0.
Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>
---
dhcp.c | 30 ++++++++++++++++++++++--------
1 file changed, 22 insertions(+), 8 deletions(-)
diff --git a/dhcp.c b/dhcp.c
index a06f143..387aee3 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -36,9 +36,9 @@
/**
* struct opt - DHCP option
* @sent: Convenience flag, set while filling replies
- * @slen: Length of option defined for server
+ * @slen: Length of option defined for server, -1 if not going to be sent
* @s: Option payload from server
- * @clen: Length of option received from client
+ * @clen: Length of option received from client, -1 if not received
* @c: Option payload from client
*/
struct opt {
@@ -68,6 +68,11 @@ static struct opt opts[255];
*/
void dhcp_init(void)
{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(opts); i++)
+ opts[i].slen = -1;
+
opts[1] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, }; /* Mask */
opts[3] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, }; /* Router */
opts[51] = (struct opt) { 0, 4, { 0xff,
@@ -154,17 +159,17 @@ static int fill(struct msg *m)
* option 53 at the beginning of the list.
* Put it there explicitly, unless requested via option 55.
*/
- if (!memchr(opts[55].c, 53, opts[55].clen))
+ if (opts[55].clen > 0 && !memchr(opts[55].c, 53, opts[55].clen))
fill_one(m, 53, &offset);
for (i = 0; i < opts[55].clen; i++) {
o = opts[55].c[i];
- if (opts[o].slen)
+ if (opts[o].slen != -1)
fill_one(m, o, &offset);
}
for (o = 0; o < 255; o++) {
- if (opts[o].slen && !opts[o].sent)
+ if (opts[o].slen != -1 && !opts[o].sent)
fill_one(m, o, &offset);
}
@@ -264,6 +269,9 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len)
".\xc0");
}
}
+
+ if (!opts[119].slen)
+ opts[119].slen = -1;
}
/**
@@ -313,6 +321,9 @@ int dhcp(const struct ctx *c, const struct pool *p)
offset += offsetof(struct msg, o);
+ for (i = 0; i < ARRAY_SIZE(opts); i++)
+ opts[i].clen = -1;
+
while (opt_off + 2 < opt_len) {
const uint8_t *olen, *val;
uint8_t *type;
@@ -331,11 +342,12 @@ int dhcp(const struct ctx *c, const struct pool *p)
opt_off += *olen + 2;
}
- if (opts[53].c[0] == DHCPDISCOVER) {
+ if (opts[53].clen > 0 && opts[53].c[0] == DHCPDISCOVER) {
info("DHCP: offer to discover");
opts[53].s[0] = DHCPOFFER;
- } else if (opts[53].c[0] == DHCPREQUEST || !opts[53].clen) {
- info("%s: ack to request", opts[53].clen ? "DHCP" :
"BOOTP");
+ } else if (opts[53].clen <= 0 || opts[53].c[0] == DHCPREQUEST) {
+ info("%s: ack to request", /* DHCP needs a valid message type */
+ (opts[53].clen <= 0) ? "BOOTP" : "DHCP");
opts[53].s[0] = DHCPACK;
} else {
return -1;
@@ -374,6 +386,8 @@ int dhcp(const struct ctx *c, const struct pool *p)
((struct in_addr *)opts[6].s)[i] = c->ip4.dns[i];
opts[6].slen += sizeof(uint32_t);
}
+ if (!opts[6].slen)
+ opts[6].slen = -1;
if (!c->no_dhcp_dns_search)
opt_set_dns_search(c, sizeof(m->o));
--
2.43.0