[Dnsmasq-discuss] [PATCH] pxe: support pxe clients with custom vendor-class
Wang Shanker
shankerwangmiao at gmail.com
Wed Dec 2 12:23:47 GMT 2020
According to UEFI[1] and PXE[2] specs, PXE clients are required to have
`PXEClient` identfier in the vendor-class field of DHCP requests, and
PXE servers should also include that identifier in their responses.
However, the firmware of servers from a few vendors[3] are customized to
include a different identifier. This patch adds an option named
`dhcp-pxe-vendor` to provide a list of such identifiers. The identifier
used in responses sent from dnsmasq is identical to that in the coresponding
request.
[1]: https://uefi.org/sites/default/files/resources/UEFI%20Spec%202.8B%20May%202020.pdf
[2]: http://www.pix.net/software/pxeboot/archive/pxespec.pdf
[3]: For instance, TaiShan servers from Huawei, which are Arm64-based,
send `HW-Client` in PXE requests up to now.
Signed-off-by: Miao Wang <shankerwangmiao at gmail.com>
---
man/dnsmasq.8 | 15 ++++++++
src/dnsmasq.h | 9 +++++
src/option.c | 27 ++++++++++++--
src/rfc2131.c | 97 +++++++++++++++++++++++++++++++++++++--------------
4 files changed, 120 insertions(+), 28 deletions(-)
diff --git a/man/dnsmasq.8 b/man/dnsmasq.8
index 2e5ef21..31ea0b4 100644
--- a/man/dnsmasq.8
+++ b/man/dnsmasq.8
@@ -1426,6 +1426,21 @@ to allow netbooting. This mode is enabled using the
.B proxy
keyword in
.B dhcp-range.
+.TP
+.B --dhcp-pxe-vendor=<vendor>[,...]
+According to UEFI and PXE specifications, DHCP packets between PXE clients and
+proxy PXE servers should have
+.I PXEClient
+in their vendor-class field. However, the firmware of computers from a few
+vendors is customized to carry a different identifier in that field. This option
+is used to consider such identifiers valid for identifying PXE clients. For
+instance
+
+.B --dhcp-pxe-vendor=PXEClient,HW-Client
+
+will enable dnsmasq to also provide proxy PXE service to those PXE clients with
+.I HW-Client
+in as their identifier.
.TP
.B \-X, --dhcp-lease-max=<number>
Limits dnsmasq to the specified maximum number of DHCP leases. The
diff --git a/src/dnsmasq.h b/src/dnsmasq.h
index 6b44e53..e654059 100644
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -768,6 +768,7 @@ struct dhcp_opt {
#define DHOPT_RFC3925 2048
#define DHOPT_TAGOK 4096
#define DHOPT_ADDR6 8192
+#define DHOPT_VENDOR_PXE 16384
struct dhcp_boot {
char *file, *sname, *tftp_sname;
@@ -784,6 +785,8 @@ struct pxe_service {
struct pxe_service *next;
};
+#define DHCP_PXE_DEF_VENDOR "PXEClient"
+
#define MATCH_VENDOR 1
#define MATCH_USER 2
#define MATCH_CIRCUIT 3
@@ -799,6 +802,11 @@ struct dhcp_vendor {
struct dhcp_vendor *next;
};
+struct dhcp_pxe_vendor {
+ char *data;
+ struct dhcp_pxe_vendor *next;
+};
+
struct dhcp_mac {
unsigned int mask;
int hwaddr_len, hwaddr_type;
@@ -967,6 +975,7 @@ extern struct daemon {
struct ra_interface *ra_interfaces;
struct dhcp_config *dhcp_conf;
struct dhcp_opt *dhcp_opts, *dhcp_match, *dhcp_opts6, *dhcp_match6;
+ struct dhcp_pxe_vendor *dhcp_pxe_vendors;
struct dhcp_vendor *dhcp_vendors;
struct dhcp_mac *dhcp_macs;
struct dhcp_boot *boot_config;
diff --git a/src/option.c b/src/option.c
index 0c38db3..0a9d18f 100644
--- a/src/option.c
+++ b/src/option.c
@@ -159,6 +159,7 @@ struct myoption {
#define LOPT_SCRIPT_ARP 347
#define LOPT_DHCPTTL 348
#define LOPT_TFTP_MTU 349
+#define LOPT_PXE_VENDOR 350
#ifdef HAVE_GETOPT_LONG
static const struct option opts[] =
@@ -257,6 +258,7 @@ static const struct myoption opts[] =
{ "dhcp-circuitid", 1, 0, LOPT_CIRCUIT },
{ "dhcp-remoteid", 1, 0, LOPT_REMOTE },
{ "dhcp-subscrid", 1, 0, LOPT_SUBSCR },
+ { "dhcp-pxe-vendor", 1, 0, LOPT_PXE_VENDOR },
{ "interface-name", 1, 0, LOPT_INTNAME },
{ "dhcp-hostsfile", 1, 0, LOPT_DHCP_HOST },
{ "dhcp-optsfile", 1, 0, LOPT_DHCP_OPTS },
@@ -367,6 +369,7 @@ static struct {
{ LOPT_CIRCUIT, ARG_DUP, "set:<tag>,<circuit>", gettext_noop("Map RFC3046 circuit-id to tag."), NULL },
{ LOPT_REMOTE, ARG_DUP, "set:<tag>,<remote>", gettext_noop("Map RFC3046 remote-id to tag."), NULL },
{ LOPT_SUBSCR, ARG_DUP, "set:<tag>,<remote>", gettext_noop("Map RFC3993 subscriber-id to tag."), NULL },
+ { LOPT_PXE_VENDOR, ARG_DUP, "<vendor>[,...]", gettext_noop("Specify vendor class to match for PXE requests."), NULL },
{ 'J', ARG_DUP, "tag:<tag>...", gettext_noop("Don't do DHCP for hosts with tag set."), NULL },
{ LOPT_BROADCAST, ARG_DUP, "[=tag:<tag>...]", gettext_noop("Force broadcast replies for hosts with tag set."), NULL },
{ 'k', OPT_NO_FORK, NULL, gettext_noop("Do NOT fork into the background, do NOT run in debug mode."), NULL },
@@ -3336,8 +3339,8 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
new->val = opt_malloc(new->len);
memcpy(new->val + 1, arg, new->len - 1);
- new->u.vendor_class = (unsigned char *)"PXEClient";
- new->flags = DHOPT_VENDOR;
+ new->u.vendor_class = NULL;
+ new->flags = DHOPT_VENDOR | DHOPT_VENDOR_PXE;
if (comma && atoi_check(comma, &timeout))
*(new->val) = timeout;
@@ -3626,6 +3629,19 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
new->next = daemon->override_relays;
daemon->override_relays = new;
arg = comma;
+ }
+ break;
+
+ case LOPT_PXE_VENDOR: /* --dhcp-pxe-vendor */
+ {
+ while (arg) {
+ struct dhcp_pxe_vendor *new = opt_malloc(sizeof(struct dhcp_pxe_vendor));
+ comma = split(arg);
+ new->data = opt_string_alloc(arg);
+ new->next = daemon->dhcp_pxe_vendors;
+ daemon->dhcp_pxe_vendors = new;
+ arg = comma;
+ }
}
break;
@@ -4762,6 +4778,13 @@ void read_opts(int argc, char **argv, char *compile_opts)
strcat(buff, daemon->authserver);
daemon->hostmaster = opt_string_alloc(buff);
}
+
+ if (!daemon->dhcp_pxe_vendors)
+ {
+ daemon->dhcp_pxe_vendors = opt_malloc(sizeof(struct dhcp_pxe_vendor));
+ daemon->dhcp_pxe_vendors->data = opt_string_alloc(DHCP_PXE_DEF_VENDOR);
+ daemon->dhcp_pxe_vendors->next = NULL;
+ }
/* only one of these need be specified: the other defaults to the host-name */
if (option_bool(OPT_LOCALMX) || daemon->mxnames || daemon->mxtarget)
diff --git a/src/rfc2131.c b/src/rfc2131.c
index 3e97402..e408337 100644
--- a/src/rfc2131.c
+++ b/src/rfc2131.c
@@ -30,7 +30,7 @@ static struct in_addr server_id(struct dhcp_context *context, struct in_addr ove
static unsigned int calc_time(struct dhcp_context *context, struct dhcp_config *config, unsigned char *opt);
static void option_put(struct dhcp_packet *mess, unsigned char *end, int opt, int len, unsigned int val);
static void option_put_string(struct dhcp_packet *mess, unsigned char *end,
- int opt, char *string, int null_term);
+ int opt, const char *string, int null_term);
static struct in_addr option_addr(unsigned char *opt);
static unsigned int option_uint(unsigned char *opt, int i, int size);
static void log_packet(char *type, void *addr, unsigned char *ext_mac,
@@ -54,16 +54,18 @@ static void do_options(struct dhcp_context *context,
int vendor_class_len,
time_t now,
unsigned int lease_time,
- unsigned short fuzz);
+ unsigned short fuzz,
+ const char *pxevendor);
static void match_vendor_opts(unsigned char *opt, struct dhcp_opt *dopt);
static int do_encap_opts(struct dhcp_opt *opts, int encap, int flag, struct dhcp_packet *mess, unsigned char *end, int null_term);
-static void pxe_misc(struct dhcp_packet *mess, unsigned char *end, unsigned char *uuid);
+static void pxe_misc(struct dhcp_packet *mess, unsigned char *end, unsigned char *uuid, const char *pxevendor);
static int prune_vendor_opts(struct dhcp_netid *netid);
static struct dhcp_opt *pxe_opts(int pxe_arch, struct dhcp_netid *netid, struct in_addr local, time_t now);
struct dhcp_boot *find_boot(struct dhcp_netid *netid);
static int pxe_uefi_workaround(int pxe_arch, struct dhcp_netid *netid, struct dhcp_packet *mess, struct in_addr local, time_t now, int pxe);
+static int is_pxe_client(struct dhcp_packet *mess, size_t sz, const char **pxe_vendor);
size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
size_t sz, time_t now, int unicast_dest, int *is_inform, int pxe, struct in_addr fallback)
@@ -74,6 +76,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
struct dhcp_mac *mac;
struct dhcp_netid_list *id_list;
int clid_len = 0, ignore = 0, do_classes = 0, selecting = 0, pxearch = -1;
+ const char *pxevendor = NULL;
struct dhcp_packet *mess = (struct dhcp_packet *)daemon->dhcp_packet.iov_base;
unsigned char *end = (unsigned char *)(mess + 1);
unsigned char *real_end = (unsigned char *)(mess + 1);
@@ -613,7 +616,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
clear_packet(mess, end, 0);
do_options(context, mess, end, NULL, hostname, get_domain(mess->yiaddr),
- netid, subnet_addr, 0, 0, -1, NULL, vendor_class_len, now, 0xffffffff, 0);
+ netid, subnet_addr, 0, 0, -1, NULL, vendor_class_len, now, 0xffffffff, 0, NULL);
}
}
@@ -770,9 +773,8 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
clid = NULL;
/* Check if client is PXE client. */
- if (daemon->enable_pxe &&
- (opt = option_find(mess, sz, OPTION_VENDOR_ID, 9)) &&
- strncmp(option_ptr(opt, 0), "PXEClient", 9) == 0)
+ if (daemon->enable_pxe &&
+ is_pxe_client(mess, sz, &pxevendor))
{
if ((opt = option_find(mess, sz, OPTION_PXE_UUID, 17)))
{
@@ -831,7 +833,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
option_put(mess, end, OPTION_MESSAGE_TYPE, 1, DHCPACK);
option_put(mess, end, OPTION_SERVER_IDENTIFIER, INADDRSZ, htonl(context->local.s_addr));
- pxe_misc(mess, end, uuid);
+ pxe_misc(mess, end, uuid, pxevendor);
prune_vendor_opts(tagif_netid);
opt71.val = save71;
@@ -911,7 +913,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
option_put(mess, end, OPTION_MESSAGE_TYPE, 1,
mess_type == DHCPDISCOVER ? DHCPOFFER : DHCPACK);
option_put(mess, end, OPTION_SERVER_IDENTIFIER, INADDRSZ, htonl(tmp->local.s_addr));
- pxe_misc(mess, end, uuid);
+ pxe_misc(mess, end, uuid, pxevendor);
prune_vendor_opts(tagif_netid);
if ((pxe && !workaround) || !redirect4011)
do_encap_opts(pxe_opts(pxearch, tagif_netid, tmp->local, now), OPTION_VENDOR_CLASS_OPT, DHOPT_VENDOR_MATCH, mess, end, 0);
@@ -1068,7 +1070,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
option_put(mess, end, OPTION_LEASE_TIME, 4, time);
/* T1 and T2 are required in DHCPOFFER by HP's wacky Jetdirect client. */
do_options(context, mess, end, req_options, offer_hostname, get_domain(mess->yiaddr),
- netid, subnet_addr, fqdn_flags, borken_opt, pxearch, uuid, vendor_class_len, now, time, fuzz);
+ netid, subnet_addr, fqdn_flags, borken_opt, pxearch, uuid, vendor_class_len, now, time, fuzz, pxevendor);
return dhcp_packet_size(mess, agent_id, real_end);
@@ -1406,7 +1408,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
option_put(mess, end, OPTION_SERVER_IDENTIFIER, INADDRSZ, ntohl(server_id(context, override, fallback).s_addr));
option_put(mess, end, OPTION_LEASE_TIME, 4, time);
do_options(context, mess, end, req_options, hostname, get_domain(mess->yiaddr),
- netid, subnet_addr, fqdn_flags, borken_opt, pxearch, uuid, vendor_class_len, now, time, fuzz);
+ netid, subnet_addr, fqdn_flags, borken_opt, pxearch, uuid, vendor_class_len, now, time, fuzz, pxevendor);
}
return dhcp_packet_size(mess, agent_id, real_end);
@@ -1471,7 +1473,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
}
do_options(context, mess, end, req_options, hostname, get_domain(mess->ciaddr),
- netid, subnet_addr, fqdn_flags, borken_opt, pxearch, uuid, vendor_class_len, now, 0xffffffff, 0);
+ netid, subnet_addr, fqdn_flags, borken_opt, pxearch, uuid, vendor_class_len, now, 0xffffffff, 0, pxevendor);
*is_inform = 1; /* handle reply differently */
return dhcp_packet_size(mess, agent_id, real_end);
@@ -1846,7 +1848,7 @@ static void option_put(struct dhcp_packet *mess, unsigned char *end, int opt, in
}
static void option_put_string(struct dhcp_packet *mess, unsigned char *end, int opt,
- char *string, int null_term)
+ const char *string, int null_term)
{
unsigned char *p;
size_t len = strlen(string);
@@ -1924,15 +1926,32 @@ static void match_vendor_opts(unsigned char *opt, struct dhcp_opt *dopt)
dopt->flags &= ~DHOPT_VENDOR_MATCH;
if (opt && (dopt->flags & DHOPT_VENDOR))
{
- int i, len = 0;
- if (dopt->u.vendor_class)
- len = strlen((char *)dopt->u.vendor_class);
- for (i = 0; i <= (option_len(opt) - len); i++)
- if (len == 0 || memcmp(dopt->u.vendor_class, option_ptr(opt, i), len) == 0)
- {
- dopt->flags |= DHOPT_VENDOR_MATCH;
- break;
- }
+ const struct dhcp_pxe_vendor *pv;
+ struct dhcp_pxe_vendor dummy_vendor = {
+ .data = (char *)dopt->u.vendor_class,
+ .next = NULL,
+ };
+ if (dopt->flags & DHOPT_VENDOR_PXE)
+ pv = daemon->dhcp_pxe_vendors;
+ else
+ pv = &dummy_vendor;
+ for (; pv; pv = pv->next)
+ {
+ int i, len = 0, matched = 0;
+ if (pv->data)
+ len = strlen(pv->data);
+ for (i = 0; i <= (option_len(opt) - len); i++)
+ if (len == 0 || memcmp(pv->data, option_ptr(opt, i), len) == 0)
+ {
+ matched = 1;
+ break;
+ }
+ if (matched)
+ {
+ dopt->flags |= DHOPT_VENDOR_MATCH;
+ break;
+ }
+ }
}
}
}
@@ -1985,11 +2004,13 @@ static int do_encap_opts(struct dhcp_opt *opt, int encap, int flag,
return ret;
}
-static void pxe_misc(struct dhcp_packet *mess, unsigned char *end, unsigned char *uuid)
+static void pxe_misc(struct dhcp_packet *mess, unsigned char *end, unsigned char *uuid, const char *pxevendor)
{
unsigned char *p;
- option_put_string(mess, end, OPTION_VENDOR_ID, "PXEClient", 0);
+ if (!pxevendor)
+ pxevendor="PXEClient";
+ option_put_string(mess, end, OPTION_VENDOR_ID, pxevendor, 0);
if (uuid && (p = free_space(mess, end, OPTION_PXE_UUID, 17)))
memcpy(p, uuid, 17);
}
@@ -2217,6 +2238,29 @@ struct dhcp_boot *find_boot(struct dhcp_netid *netid)
return boot;
}
+static int is_pxe_client(struct dhcp_packet *mess, size_t sz, const char **pxe_vendor)
+{
+ const unsigned char *opt = NULL;
+ ssize_t conf_len = 0;
+ const struct dhcp_pxe_vendor *conf = daemon->dhcp_pxe_vendors;
+ opt = option_find(mess, sz, OPTION_VENDOR_ID, 0);
+ if (!opt)
+ return 0;
+ for (; conf; conf = conf->next)
+ {
+ conf_len = strlen(conf->data);
+ if (option_len(opt) < conf_len)
+ continue;
+ if (strncmp(option_ptr(opt, 0), conf->data, conf_len) == 0)
+ {
+ if (pxe_vendor)
+ *pxe_vendor = conf->data;
+ return 1;
+ }
+ }
+ return 0;
+}
+
static void do_options(struct dhcp_context *context,
struct dhcp_packet *mess,
unsigned char *end,
@@ -2231,7 +2275,8 @@ static void do_options(struct dhcp_context *context,
int vendor_class_len,
time_t now,
unsigned int lease_time,
- unsigned short fuzz)
+ unsigned short fuzz,
+ const char *pxevendor)
{
struct dhcp_opt *opt, *config_opts = daemon->dhcp_opts;
struct dhcp_boot *boot;
@@ -2605,7 +2650,7 @@ static void do_options(struct dhcp_context *context,
if (context && pxe_arch != -1)
{
- pxe_misc(mess, end, uuid);
+ pxe_misc(mess, end, uuid, pxevendor);
if (!pxe_uefi_workaround(pxe_arch, tagif, mess, context->local, now, 0))
config_opts = pxe_opts(pxe_arch, tagif, context->local, now);
}
--
2.28.0
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