Re: [PATCH v3 6/6] doc: Add --dhcp-boot and --dhcp-opt to man page

On Mon, 1 Jun 2026 13:07:56 +0530 Anshu Kumari wrote:

Document the new --dhcp-boot and --dhcp-opt command-line options in the passt(1) man page, including supported option codes grouped by value type and usage examples.

Link: https://bugs.passt.top/show_bug.cgi?id=192 Signed-off-by: Anshu Kumari --- v3: - Removed options 33, 55, 61, 119 from supported codes list - Added note: "If the same name option code is given more than once, the last value wins".

v2: - Updated --dhcp-boot description. - Highlighted cross-referenced options with \fB...\fR. - Updated IP list format from "space-separated within quotes" to "comma-separated". - option 121 dropped. - Added option 55 to string options list. - Removed --dhcp-boot override reference from --dhcp-opt description. --- passt.1 | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+)

diff --git a/passt.1 b/passt.1 index 908fd4a..57e2cc1 100644 --- a/passt.1 +++ b/passt.1 @@ -430,6 +430,47 @@ 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 \-\-dhcp-boot " " \fIurl +Convenience shorthand for \fB\-\-dhcp-opt\fR 67,\fIurl\fR. +Sets the boot file name (DHCP option 67) for network boot. +For UEFI HTTP boot, also set the vendor class identifier using +\fB\-\-dhcp-opt\fR 60,HTTPClient.

This is ambiguous. The man page is written in an imperative style in the sense of what the tool is supposed to do, but this becomes a recommendation to the user instead (this sentence says "set" and not "sets" but that's very easy to miss, and ambiguous nevertheless). This would be clearer I think: For UEFI HTTP boot, the vendor class identifier also needs to be set using ...

+ +.TP +.BR \-\-dhcp-opt " " \fICODE\fR,\fIVALUE\fR +Set a DHCP option by numeric code. The value format is determined automatically +from the option code. Multiple IPv4 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. Options set with +\fB\-\-dhcp-opt\fR override built-in values. +Only the following option codes are supported (unsupported codes cause an error):

By the way, eventually, I think it would be nice to support those as hex encoding, maybe with a --dhcp-opt-raw parameter taking a length value (also comma-separated, say, CODE,LENGTH,VALUE). I guess it's beyond the scope of this series though.

+.RS +.TP +.B IPv4 address options +1 (Subnet Mask), 16 (Swap Server), 28 (Broadcast Address), 50 (Requested IP), +54 (Server Identifier) +.TP +.B IPv4 address list options (comma-separated) +3 (Router), 4 (Time Server), 5 (Name Server), 6 (DNS), 7 (Log Server), +8 (Cookie Server), 9 (LPR Server), 10 (Impress Server), +11 (Resource Location Server), 41 (NIS Servers), +42 (NTP Servers), 44 (NetBIOS Name Server) +.TP +.B Integer options +2 (Time Offset, 32-bit), 13 (Boot File Size, 16-bit), 19 (IP Forwarding, 8-bit), +23 (Default IP TTL, 8-bit), 26 (Interface MTU, 16-bit), +37 (TCP Default TTL, 8-bit), 38 (TCP Keepalive Interval, 32-bit), +51 (IP Address Lease Time, 32-bit), +53 (DHCP Message Type, 8-bit), 57 (Max DHCP Message Size, 16-bit), +58 (Renewal Time, 32-bit), 59 (Rebinding Time, 32-bit) +.TP +.B String options +12 (Host Name), 15 (Domain Name), 17 (Root Path), 40 (NIS Domain Name), +60 (Vendor Class Identifier), 66 (TFTP Server Name), +67 (Bootfile Name), 252 (WPAD URL) +.RE + .TP .BR \-t ", " \-\-tcp-ports " " \fIspec Configure TCP port forwarding to guest or namespace. \fIspec\fR can be one of:

The rest looks good to me. -- Stefano