Add a type table mapping DHCPv6 option codes to value types,
and a parser that encodes CLI strings into the correct binary wire
format for each type.
Supported types: plain string, IPv6 address, IPv6 address list,
8/16/32-bit integers, vendor class (enterprise number + length-prefixed
data, per RFC 8415 Section 21.16), status code (uint16 + message),
and length-prefixed string lists.
Modify dhcpv6_add_option() to call the parser for validation and binary
encoding at configuration time, storing both the raw string and the
encoded value.
Signed-off-by: Anshu Kumari
---
dhcpv6.c | 228 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
passt.1 | 28 ++++++-
passt.h | 4 +
3 files changed, 255 insertions(+), 5 deletions(-)
diff --git a/dhcpv6.c b/dhcpv6.c
index a0fb77c..85e2926 100644
--- a/dhcpv6.c
+++ b/dhcpv6.c
@@ -25,6 +25,7 @@
#include
#include
#include
+#include
#include "packet.h"
#include "util.h"
@@ -32,20 +33,233 @@
#include "tap.h"
#include "log.h"
+/**
+ * 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[256] = {
+ [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
+ */
+static int dhcpv6_opt_parse(uint16_t code, const char *str,
+ uint8_t *buf, size_t buf_len)
+{
+ char chunk[INET6_ADDRSTRLEN];
+ enum dhcpv6_opt_type type;
+ unsigned long val;
+ const char *colon;
+ unsigned int i;
+ uint8_t width;
+ size_t slen;
+ char *end;
+ int len;
+
+ if (!*str)
+ die("Empty value for DHCPv6 option %u", code);
+
+ if (code >= ARRAY_SIZE(dhcpv6_opt_types))
+ die("Unsupported DHCPv6 option: %u,"
+ " see passt(1) for supported codes", code);
+
+ type = dhcpv6_opt_types[code];
+
+ switch (type) {
+ case DHCPV6_OPT_NONE:
+ die("Unsupported DHCPv6 option: %u,"
+ " see passt(1) for supported codes", code);
+ case DHCPV6_OPT_IPV6:
+ case DHCPV6_OPT_IPV6_LIST:
+ len = 0;
+
+ while (*str) {
+ slen = strcspn(str, ",");
+ if (!slen || slen >= sizeof(chunk))
+ return -1;
+
+ if (len + (int)sizeof(struct in6_addr) > (int)buf_len)
+ return -1;
+
+ memcpy(chunk, str, slen);
+ chunk[slen] = '\0';
+
+ if (inet_pton(AF_INET6, chunk,
+ buf + len) != 1)
+ return -1;
+
+ len += sizeof(struct in6_addr);
+
+ if (type == DHCPV6_OPT_IPV6) {
+ if (str[slen] == ',')
+ return -1;
+ break;
+ }
+
+ str += slen;
+ if (*str == ',')
+ str++;
+ }
+
+ 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;
+
+ errno = 0;
+ val = strtoul(str, &end, 0);
+
+ if (*end || errno)
+ return -1;
+
+ if (buf_len < width)
+ return -1;
+
+ if (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 || slen >= buf_len)
+ return -1;
+
+ memcpy(buf, str, slen);
+
+ return slen;
+ case DHCPV6_OPT_VENDOR_CLASS:
+ 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;
+
+ uint32_t 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_add_option() - Add or update a custom DHCPv6 option
* @c: Execution context
* @code: DHCPv6 option code
* @val_str: Value string from command line
*
- * Stores the option code and raw string value. Binary encoding and
- * injection into DHCPv6 replies are handled by later patches.
+ * Parses @val_str according to the type registered for @code in
+ * dhcpv6_opt_types[]. If @code was already added, the previous value
+ * is overwritten.
*
* Return: 0 on success
*/
int dhcpv6_add_option(struct ctx *c, uint16_t code, const char *val_str)
{
- int idx;
+ int idx, ret;
for (idx = 0; idx < c->custom_v6opts_count; idx++) {
if (c->custom_v6opts[idx].code == code)
@@ -59,7 +273,15 @@ int dhcpv6_add_option(struct ctx *c, uint16_t code, const char *val_str)
c->custom_v6opts_count++;
}
+ ret = dhcpv6_opt_parse(code, val_str,
+ c->custom_v6opts[idx].val,
+ sizeof(c->custom_v6opts[0].val));
+ if (ret < 0)
+ die("Invalid value for DHCPv6 option %u: %s",
+ code, val_str);
+
c->custom_v6opts[idx].code = code;
+ c->custom_v6opts[idx].len = ret;
if (snprintf_check(c->custom_v6opts[idx].str,
sizeof(c->custom_v6opts[0].str),
diff --git a/passt.1 b/passt.1
index 9c25214..3c4f3ac 100644
--- a/passt.1
+++ b/passt.1
@@ -433,8 +433,32 @@ Send \fIname\fR as Client FQDN: DHCP option 81 and DHCPv6 option 39.
.TP
.BR \-\-dhcpv6-opt " " \fICODE\fR,\fIVALUE\fR
Set a DHCPv6 option by numeric code. The value format is determined
-automatically from the option code. This option can be specified multiple
-times. If the same option code is given more than once, the last value wins.
+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
diff --git a/passt.h b/passt.h
index 91509df..21f43d8 100644
--- a/passt.h
+++ b/passt.h
@@ -184,6 +184,8 @@ struct ip6_ctx {
* @fqdn: Guest FQDN
* @custom_v6opts: User-specified DHCPv6 options from --dhcpv6-opt
* @custom_v6opts.code: DHCPv6 option code
+ * @custom_v6opts.len: Length of binary value in @val
+ * @custom_v6opts.val: Binary-encoded option value
* @custom_v6opts.str: Original string value from command line
* @custom_v6opts_count:Number of entries in @custom_v6opts
* @ifi6: Template interface for IPv6, -1: none, 0: IPv6 disabled
@@ -271,6 +273,8 @@ struct ctx {
struct {
uint16_t code;
+ uint16_t len;
+ uint8_t val[255];
char str[256];
} custom_v6opts[MAX_CUSTOM_DHCPV6_OPTS];
int custom_v6opts_count;
--
2.54.0