Introduce the --dhcp-opt flag that allows setting arbitrary DHCP
options from command-line in the form of [Option CODE,VALUE].
This patch adds the option storage in struct ctx and CLI parsing;
the type-aware value parser and DHCP reply injection follow
in subsequent patches.
Link: https://bugs.passt.top/show_bug.cgi?id=192
Signed-off-by: Anshu Kumari
---
conf.c | 36 +++++++++++++++++++++++++++++++++++-
passt.h | 10 ++++++++++
2 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/conf.c b/conf.c
index 029b9c7..2624e58 100644
--- a/conf.c
+++ b/conf.c
@@ -47,6 +47,7 @@
#include "lineread.h"
#include "isolation.h"
#include "log.h"
+#include "dhcp.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"
+ " --dhcp-opt CODE,VAL Set DHCP option by code\n");
if (strstr(name, "pasta"))
FPRINTF(f, " default: don't use any search list\n");
else
@@ -844,6 +846,10 @@ static void conf_print(const struct ctx *c)
info(" router: %s",
inet_ntop(AF_INET, &c->ip4.guest_gw,
buf, sizeof(buf)));
+ for (i = 0; i < c->custom_opts_count; i++)
+ info(" option %u: %s",
+ c->custom_opts[i].code,
+ c->custom_opts[i].str);
}
for (i = 0; i < ARRAY_SIZE(c->ip4.dns); i++) {
@@ -1233,6 +1239,7 @@ 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' },
+ {"dhcp-opt", required_argument, NULL, 33 },
{ 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:";
@@ -1465,6 +1472,33 @@ 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 33: {
+ unsigned long code;
+ const char *comma;
+ char *end;
+
+ comma = strchr(optarg, ',');
+ if (!comma)
+ die("--dhcp-opt requires Option CODE,VALUE format");
+
+ code = strtoul(optarg, &end, 0);
+ if (end != comma || code < 1 || code > 254)
+ die("DHCP option code must be 1-254: %s",
+ optarg);
+
+ if (c->custom_opts_count >= MAX_CUSTOM_DHCP_OPTS)
+ die("Too many --dhcp-opt entries (max %d)",
+ MAX_CUSTOM_DHCP_OPTS);
+
+ c->custom_opts[c->custom_opts_count].code = code;
+ if (snprintf_check(c->custom_opts[c->custom_opts_count].str,
+ sizeof(c->custom_opts[0].str),
+ "%s", comma + 1))
+ die("DHCP option value too long: %s",
+ comma + 1);
+ c->custom_opts_count++;
+ break;
+ }
case 'd':
c->debug = 1;
c->quiet = 0;
diff --git a/passt.h b/passt.h
index 1726965..acb57dd 100644
--- a/passt.h
+++ b/passt.h
@@ -263,6 +263,16 @@ struct ctx {
char hostname[PASST_MAXDNAME];
char fqdn[PASST_MAXDNAME];
+#define MAX_CUSTOM_DHCP_OPTS 32
+
+ struct {
+ uint8_t code;
+ uint8_t len;
+ uint8_t val[255];
+ char str[256];
+ } custom_opts[MAX_CUSTOM_DHCP_OPTS];
+ int custom_opts_count;
+
int ifi6;
struct ip6_ctx ip6;
--
2.54.0