Introduce the --dhcpv6-opt flag that allows setting arbitrary DHCPv6
options from command-line in the form [--dhcpv6-opt CODE,VALUE].
Add a type lookup table mapping option codes to value types (IPv6,
IPv6 list, integer, string, vendor class, length-prefixed string
list) and dhcpv6_opt_parse() to convert CLI strings to binary wire
format. If the same option code is given more than once, the
last value wins.
Link: https://bugs.passt.top/show_bug.cgi?id=192
Signed-off-by: Anshu Kumari
---
v2:
- Renamed custom_v6opts to dhcpv6_opts, MAX_CUSTOM_DHCPV6_OPTS
to MAX_DHCPV6_OPTS.
- Dropped val/len from ctx struct.
- Moved dhcpv6_add_option() to conf.c as static
conf_dhcpv6_option().
- Made dhcpv6_opt_parse() non-static, declared in dhcpv6.h
- Omitted explicit [256] from dhcpv6_opt_types[].
- Moved chunk declaration into while block.
- Removed redundant !slen check in DHCPV6_OPT_STR case.
- All errors in dhcpv6_opt_parse() return -1, removed die()
calls.
---
conf.c | 60 +++++++++++++++-
dhcpv6.c | 209 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
dhcpv6.h | 2 +
passt.1 | 31 +++++++++
passt.h | 12 ++++
5 files changed, 313 insertions(+), 1 deletion(-)
diff --git a/conf.c b/conf.c
index cd05adf..3981c1b 100644
--- a/conf.c
+++ b/conf.c
@@ -47,6 +47,7 @@
#include "lineread.h"
#include "isolation.h"
#include "log.h"
+#include "dhcpv6.h"
#include "vhost_user.h"
#include "epoll_ctl.h"
#include "conf.h"
@@ -616,7 +617,8 @@ static void usage(const char *name, FILE *f, int status)
" -S, --search LIST Space-separated list, search domains\n"
" a single, empty option disables the DNS search list\n"
" -H, --hostname NAME Hostname to configure client with\n"
- " --fqdn NAME FQDN to configure client with\n");
+ " --fqdn NAME FQDN to configure client with\n"
+ " --dhcpv6-opt CODE,VAL Set DHCPv6 option CODE to VAL\n");
if (strstr(name, "pasta"))
FPRINTF(f, " default: don't use any search list\n");
else
@@ -884,6 +886,10 @@ static void conf_print(const struct ctx *c)
info(" our link-local: %s",
inet_ntop(AF_INET6, &c->ip6.our_tap_ll,
buf, sizeof(buf)));
+ for (i = 0; i < c->dhcpv6_opts_count; i++)
+ info(" v6 option %u: %s",
+ c->dhcpv6_opts[i].code,
+ c->dhcpv6_opts[i].str);
dns6:
for (i = 0; i < ARRAY_SIZE(c->ip6.dns); i++) {
@@ -1150,6 +1156,41 @@ static void conf_sock_listen(const struct ctx *c)
die_perror("Couldn't add configuration socket to epoll");
}
+/**
+ * conf_dhcpv6_option() - Set value for a DHCPv6 option in configuration
+ * @c: Execution context
+ * @code: DHCPv6 option code
+ * @val_str: Value string from command line
+ */
+static void conf_dhcpv6_option(struct ctx *c, uint16_t code,
+ const char *val_str)
+{
+ uint8_t tmp[255];
+ int idx;
+
+ if (dhcpv6_opt_parse(code, val_str, tmp, sizeof(tmp)) < 0)
+ die("Invalid value for DHCPv6 option %u: %s", code, val_str);
+
+ for (idx = 0; idx < c->dhcpv6_opts_count; idx++) {
+ if (c->dhcpv6_opts[idx].code == code)
+ break;
+ }
+
+ if (idx == c->dhcpv6_opts_count) {
+ if (c->dhcpv6_opts_count >= MAX_DHCPV6_OPTS)
+ die("Too many --dhcpv6-opt entries (max %d)",
+ MAX_DHCPV6_OPTS);
+ c->dhcpv6_opts_count++;
+ }
+
+ c->dhcpv6_opts[idx].code = code;
+
+ if (snprintf_check(c->dhcpv6_opts[idx].str,
+ sizeof(c->dhcpv6_opts[0].str),
+ "%s", val_str))
+ die("DHCPv6 option value too long: %s", val_str);
+}
+
/**
* conf() - Process command-line arguments and set configuration
* @c: Execution context
@@ -1233,6 +1274,7 @@ void conf(struct ctx *c, int argc, char **argv)
{"migrate-no-linger", no_argument, NULL, 30 },
{"stats", required_argument, NULL, 31 },
{"conf-path", required_argument, NULL, 'c' },
+ {"dhcpv6-opt", required_argument, NULL, 35 },
{ 0 },
};
const char *optstring = "+dqfel:hs:c:F:I:p:P:m:a:n:M:g:i:o:D:S:H:461t:u:T:U:";
@@ -1248,10 +1290,13 @@ void conf(struct ctx *c, int argc, char **argv)
uint8_t prefix_len_from_opt = 0;
unsigned int ifi4 = 0, ifi6 = 0;
const char *logfile = NULL;
+ unsigned long v6optcode;
char *runas = NULL;
size_t logsize = 0;
+ const char *comma;
long fd_tap_opt;
int name, ret;
+ char *end;
uid_t uid;
gid_t gid;
@@ -1467,6 +1512,19 @@ void conf(struct ctx *c, int argc, char **argv)
die("Can't display statistics if not running in foreground");
c->stats = strtol(optarg, NULL, 0);
break;
+ case 35:
+ comma = strchr(optarg, ',');
+ if (!comma)
+ die("--dhcpv6-opt requires CODE,VALUE format");
+
+ errno = 0;
+ v6optcode = strtoul(optarg, &end, 0);
+ if (end != comma || errno || v6optcode < 1)
+ die("Invalid DHCPv6 option code: %s",
+ optarg);
+
+ conf_dhcpv6_option(c, v6optcode, comma + 1);
+ break;
case 'd':
c->debug = 1;
c->quiet = 0;
diff --git a/dhcpv6.c b/dhcpv6.c
index 97c04e2..1e1dd0d 100644
--- a/dhcpv6.c
+++ b/dhcpv6.c
@@ -25,6 +25,7 @@
#include
#include
#include
+#include
#include "packet.h"
#include "util.h"
@@ -278,6 +279,214 @@ static struct resp_not_on_link_t {
{ 0, },
};
+/**
+ * enum dhcpv6_opt_type - DHCPv6 option value types
+ * @DHCPV6_OPT_NONE: Unsupported or unknown option
+ * @DHCPV6_OPT_STR: Variable-length string
+ * @DHCPV6_OPT_IPV6: Single IPv6 address
+ * @DHCPV6_OPT_IPV6_LIST: Multiple IPv6 addresses, comma-separated
+ * @DHCPV6_OPT_INT8: Unsigned 8-bit integer
+ * @DHCPV6_OPT_INT16: Unsigned 16-bit integer
+ * @DHCPV6_OPT_INT32: Unsigned 32-bit integer
+ * @DHCPV6_OPT_VENDOR_CLASS: Enterprise number + length-prefixed data
+ * @DHCPV6_OPT_LEN_STR_LIST: Length-prefixed string list
+ */
+enum dhcpv6_opt_type {
+ DHCPV6_OPT_NONE,
+ DHCPV6_OPT_STR,
+ DHCPV6_OPT_IPV6,
+ DHCPV6_OPT_IPV6_LIST,
+ DHCPV6_OPT_INT8,
+ DHCPV6_OPT_INT16,
+ DHCPV6_OPT_INT32,
+ DHCPV6_OPT_VENDOR_CLASS,
+ DHCPV6_OPT_LEN_STR_LIST,
+};
+
+/**
+ * dhcpv6_opt_types - Maps DHCPv6 option code to value type, indexed by code
+ * RFC 8415 Options: 7, 15, 16, 17, 32, 82, 83
+ * RFC 5970 Options: 59, 60
+ * RFC 4075 Options: 31
+ */
+static const enum dhcpv6_opt_type dhcpv6_opt_types[] = {
+ [7] = DHCPV6_OPT_INT8, /* Preference */
+ [15] = DHCPV6_OPT_LEN_STR_LIST, /* User Class */
+ [16] = DHCPV6_OPT_VENDOR_CLASS, /* Vendor Class */
+ [17] = DHCPV6_OPT_VENDOR_CLASS, /* Vendor Opts */
+ [31] = DHCPV6_OPT_IPV6_LIST, /* SNTP Servers */
+ [32] = DHCPV6_OPT_INT32, /* Information Refresh Time */
+ [59] = DHCPV6_OPT_STR, /* Boot File URL */
+ [60] = DHCPV6_OPT_LEN_STR_LIST, /* Boot File Params */
+ [82] = DHCPV6_OPT_INT32, /* SOL_MAX_RT */
+ [83] = DHCPV6_OPT_INT32, /* INF_MAX_RT */
+};
+
+/**
+ * dhcpv6_opt_parse() - Parse a DHCPv6 option value string into binary
+ * @code: DHCPv6 option code
+ * @str: Value string from command line
+ * @buf: Output buffer for binary value
+ * @buf_len: Size of output buffer
+ *
+ * Return: number of bytes written to @buf, or -1 on error
+ */
+int dhcpv6_opt_parse(uint16_t code, const char *str,
+ uint8_t *buf, size_t buf_len)
+{
+ enum dhcpv6_opt_type type;
+ unsigned long val;
+ unsigned int i;
+ uint8_t width;
+ size_t slen;
+ char *end;
+ int len;
+
+ if (!*str)
+ return -1;
+
+ if (code >= ARRAY_SIZE(dhcpv6_opt_types))
+ return -1;
+
+ type = dhcpv6_opt_types[code];
+
+ switch (type) {
+ case DHCPV6_OPT_NONE:
+ return -1;
+ case DHCPV6_OPT_IPV6:
+ case DHCPV6_OPT_IPV6_LIST:
+ len = 0;
+
+ while (*str) {
+ char chunk[INET6_ADDRSTRLEN];
+ size_t clen;
+
+ clen = strcspn(str, ",");
+ if (!clen || clen >= sizeof(chunk))
+ return -1;
+
+ if (len + (int)sizeof(struct in6_addr) > (int)buf_len)
+ return -1;
+
+ memcpy(chunk, str, clen);
+ chunk[clen] = '\0';
+
+ if (inet_pton(AF_INET6, chunk, buf + len) != 1)
+ return -1;
+
+ len += sizeof(struct in6_addr);
+
+ if (type == DHCPV6_OPT_IPV6) {
+ if (str[clen] == ',')
+ return -1;
+ break;
+ }
+
+ str += clen + (str[clen] == ',');
+ }
+
+ if (!len)
+ return -1;
+
+ return len;
+ case DHCPV6_OPT_INT8:
+ case DHCPV6_OPT_INT16:
+ case DHCPV6_OPT_INT32:
+ if (type == DHCPV6_OPT_INT8)
+ width = 1;
+ else if (type == DHCPV6_OPT_INT16)
+ width = 2;
+ else
+ width = 4;
+
+ if (buf_len < width)
+ return -1;
+
+ errno = 0;
+ val = strtoul(str, &end, 0);
+
+ if (*end || errno || val >= (1ULL << (width * 8)))
+ return -1;
+
+ for (i = width; i > 0; i--) {
+ buf[i - 1] = val & 0xff;
+ val >>= 8;
+ }
+
+ return width;
+ case DHCPV6_OPT_STR:
+ slen = strlen(str);
+
+ if (slen >= buf_len)
+ return -1;
+
+ memcpy(buf, str, slen);
+
+ return slen;
+ case DHCPV6_OPT_VENDOR_CLASS: {
+ const char *colon;
+ uint32_t ent;
+
+ colon = strchr(str, ':');
+ if (!colon)
+ return -1;
+
+ errno = 0;
+ val = strtoul(str, &end, 0);
+ if (end != colon || errno || val > UINT32_MAX)
+ return -1;
+
+ slen = strlen(colon + 1);
+ if (!slen)
+ return -1;
+
+ len = sizeof(uint32_t) + sizeof(uint16_t) + slen;
+ if ((size_t)len > buf_len)
+ return -1;
+
+ ent = htonl(val);
+ memcpy(buf, &ent, sizeof(ent));
+
+ buf[4] = slen >> 8;
+ buf[5] = slen & 0xff;
+
+ memcpy(buf + sizeof(uint32_t) + sizeof(uint16_t),
+ colon + 1, slen);
+
+ return len;
+ }
+ case DHCPV6_OPT_LEN_STR_LIST:
+ len = 0;
+
+ while (*str) {
+ slen = strcspn(str, ",");
+ if (!slen)
+ return -1;
+
+ if (len + (int)(sizeof(uint16_t) + slen) > (int)buf_len)
+ return -1;
+
+ buf[len] = slen >> 8;
+ buf[len + 1] = slen & 0xff;
+ len += sizeof(uint16_t);
+
+ memcpy(buf + len, str, slen);
+ len += slen;
+
+ str += slen;
+ if (*str == ',')
+ str++;
+ }
+
+ if (!len)
+ return -1;
+
+ return len;
+ }
+
+ return -1;
+}
+
/**
* dhcpv6_opt() - Get option from DHCPv6 message
* @data: Buffer with options, set to matching option on return
diff --git a/dhcpv6.h b/dhcpv6.h
index c706dfd..2da1c76 100644
--- a/dhcpv6.h
+++ b/dhcpv6.h
@@ -9,5 +9,7 @@
int dhcpv6(struct ctx *c, struct iov_tail *data,
struct in6_addr *saddr, struct in6_addr *daddr);
void dhcpv6_init(const struct ctx *c);
+int dhcpv6_opt_parse(uint16_t code, const char *str,
+ uint8_t *buf, size_t buf_len);
#endif /* DHCPV6_H */
diff --git a/passt.1 b/passt.1
index 908fd4a..0f771cb 100644
--- a/passt.1
+++ b/passt.1
@@ -430,6 +430,37 @@ Send \fIname\fR as DHCP option 12 (hostname).
FQDN to configure the client with.
Send \fIname\fR as Client FQDN: DHCP option 81 and DHCPv6 option 39.
+.TP
+.BR \-\-dhcpv6-opt " " \fICODE\fR,\fIVALUE\fR
+Set DHCPv6 option \fICODE\fR to \fIVALUE\fR. The value format depends
+on the option type and is determined automatically from the option code.
+Multiple IPv6 addresses are comma-separated.
+This option can be specified multiple times. If the same option code is
+given more than once, the last value wins.
+.RS
+.TP
+.B String options
+59 (Boot File URL, RFC 5970)
+.TP
+.B Length-prefixed string list options (comma-separated entries)
+15 (User Class, RFC 8415), 60 (Boot File Params, RFC 5970).
+Each comma-separated entry is encoded with a 2-byte length prefix.
+Example: \fB\-\-dhcpv6-opt 15,class1,class2\fR.
+.TP
+.B Vendor class options (ENTERPRISE:DATA format)
+16 (Vendor Class, RFC 8415), 17 (Vendor-specific Info, RFC 8415).
+VALUE is \fIENTERPRISE\fR:\fIDATA\fR where \fIENTERPRISE\fR is the IANA
+Private Enterprise Number and \fIDATA\fR is the vendor class string.
+Example: \fB\-\-dhcpv6-opt 16,0:HTTPClient\fR for UEFI HTTP Boot.
+.TP
+.B IPv6 address list options (comma-separated)
+31 (SNTP Servers)
+.TP
+.B Integer options
+7 (Preference, 8-bit), 32 (Information Refresh Time, 32-bit),
+82 (SOL_MAX_RT, 32-bit), 83 (INF_MAX_RT, 32-bit)
+.RE
+
.TP
.BR \-t ", " \-\-tcp-ports " " \fIspec
Configure TCP port forwarding to guest or namespace. \fIspec\fR can be one of:
diff --git a/passt.h b/passt.h
index 3a07294..8f4ddef 100644
--- a/passt.h
+++ b/passt.h
@@ -182,6 +182,10 @@ struct ip6_ctx {
* @dns_search: DNS search list
* @hostname: Guest hostname
* @fqdn: Guest FQDN
+ * @dhcpv6_opts: User-specified DHCPv6 options from --dhcpv6-opt
+ * @dhcpv6_opts.code: DHCPv6 option code
+ * @dhcpv6_opts.str: String value from command line
+ * @dhcpv6_opts_count: Number of entries in @dhcpv6_opts
* @ifi6: Template interface for IPv6, -1: none, 0: IPv6 disabled
* @ip6: IPv6 configuration
* @pasta_ifn: Name of namespace interface for pasta
@@ -264,6 +268,14 @@ struct ctx {
char hostname[PASST_MAXDNAME];
char fqdn[PASST_MAXDNAME];
+#define MAX_DHCPV6_OPTS 32
+
+ struct {
+ uint16_t code;
+ char str[255];
+ } dhcpv6_opts[MAX_DHCPV6_OPTS];
+ int dhcpv6_opts_count;
+
int ifi6;
struct ip6_ctx ip6;
--
2.54.0