On 2023-11-04 12:53 a.m., Heinrich Schuchardt wrote:
On 11/4/23 03:03, Sean Edmond wrote:
On 2023-10-23 10:54 p.m., Heinrich Schuchardt wrote:
On 10/24/23 02:21, seanedmond@linux.microsoft.com wrote:
From: Sean Edmond seanedmond@microsoft.com
Allow dhcp server pass pxe config file full path by using option 209
Signed-off-by: Sean Edmond seanedmond@microsoft.com
cmd/Kconfig | 4 ++++ cmd/pxe.c | 10 ++++++++++ net/bootp.c | 21 +++++++++++++++++++++ 3 files changed, 35 insertions(+)
diff --git a/cmd/Kconfig b/cmd/Kconfig index 5bc0a92d57..adbb1a6187 100644 --- a/cmd/Kconfig +++ b/cmd/Kconfig @@ -1826,6 +1826,10 @@ config BOOTP_PXE_CLIENTARCH default 0x15 if ARM default 0x0 if X86
+config BOOTP_PXE_DHCP_OPTION + bool "Request & store 'pxe_configfile' from BOOTP/DHCP server" + depends on BOOTP_PXE
Why should this be disabled by default?
Do we really want a separate config variable?
I expect most won't use this option to get the file path (they'll use the default paths as per the PXE specification). It makes more sense for me to keep it optional, like many of the other options?
RFC 5701 seems to require this option. Hence we should make it default yes. Boards that have a build size issue can opt out.
The PXELINUX specification (https://wiki.syslinux.org/wiki/index.php?title=PXELINUX) doesn't state that option 209 is required. In the abense of option 209, PXELINUX will try the following default configuration files (this example is provided on the wiki link): /mybootdir/pxelinux.cfg/b8945908-d6a6-41a9-611d-74a6ab80b83d /mybootdir/pxelinux.cfg/01-88-99-aa-bb-cc-dd /mybootdir/pxelinux.cfg/C0A8025B /mybootdir/pxelinux.cfg/C0A8025 /mybootdir/pxelinux.cfg/C0A802 /mybootdir/pxelinux.cfg/C0A80 /mybootdir/pxelinux.cfg/C0A8 /mybootdir/pxelinux.cfg/C0A /mybootdir/pxelinux.cfg/C0 /mybootdir/pxelinux.cfg/C /mybootdir/pxelinux.cfg/default
If 209 is requested/provided it tries the provided "config file" before the default paths. RFC 5071 should be seen as an extension for PXELINUX (not a requirement). RFC 5071 only states "The Config File Option MUST be supplied by the DHCP server if it appears on the Parameter Request List".
Best regards
Heinrich
config BOOTP_VCI_STRING string depends on CMD_BOOTP diff --git a/cmd/pxe.c b/cmd/pxe.c index 704589702f..9404f44518 100644 --- a/cmd/pxe.c +++ b/cmd/pxe.c @@ -65,6 +65,8 @@ static int pxe_dhcp_option_path(struct pxe_context *ctx, unsigned long pxefile_a int ret = get_pxe_file(ctx, pxelinux_configfile, pxefile_addr_r);
free(pxelinux_configfile); + /* set to NULL to avoid double-free if DHCP is tried again */ + pxelinux_configfile = NULL;
return ret; } @@ -141,6 +143,14 @@ int pxe_get(ulong pxefile_addr_r, char **bootdirp, ulong *sizep, bool use_ipv6) env_get("bootfile"), use_ipv6)) return -ENOMEM;
+ if (IS_ENABLED(CONFIG_BOOTP_PXE_DHCP_OPTION) && + pxelinux_configfile && !use_ipv6) { + if (pxe_dhcp_option_path(&ctx, pxefile_addr_r) > 0) + goto done;
+ goto error_exit; + }
if (IS_ENABLED(CONFIG_DHCP6_PXE_DHCP_OPTION) && pxelinux_configfile && use_ipv6) { if (pxe_dhcp_option_path(&ctx, pxefile_addr_r) > 0) diff --git a/net/bootp.c b/net/bootp.c index 7b0f45e18a..6800290963 100644 --- a/net/bootp.c +++ b/net/bootp.c @@ -26,6 +26,7 @@ #ifdef CONFIG_BOOTP_RANDOM_DELAY #include "net_rand.h" #endif +#include <malloc.h>
#define BOOTP_VENDOR_MAGIC 0x63825363 /* RFC1048 Magic Cookie */
@@ -601,6 +602,10 @@ static int dhcp_extended(u8 *e, int message_type, struct in_addr server_ip, *e++ = 42; *cnt += 1; #endif + if (IS_ENABLED(CONFIG_BOOTP_PXE_DHCP_OPTION)) { + *e++ = 209; /* PXELINUX Config File */ + *cnt += 1; + } /* no options, so back up to avoid sending an empty request list */ if (*cnt == 0) e -= 2; @@ -909,6 +914,22 @@ static void dhcp_process_options(uchar *popt, uchar *end) net_boot_file_name[size] = 0; } break; + case 209: /* PXELINUX Config File */
This 209 appears in multiple places. Please, define a constant, e.g. DHCP_OPTION_CONFIG_FILE, in bootp.h and use the symbolic name. Please, document the constant referring to RFC 5071.
fixed in v3.
+ if (IS_ENABLED(CONFIG_BOOTP_PXE_DHCP_OPTION)) { + /* In case it has already been allocated when get DHCP Offer packet, + * free first to avoid memory leak. + */ + if (pxelinux_configfile) + free(pxelinux_configfile);
+ pxelinux_configfile = (char *)malloc((oplen + 1) * sizeof(char));
+ if (pxelinux_configfile) + strlcpy(pxelinux_configfile, popt + 2, oplen + 1); + else + printf("Error: Failed to allocate pxelinux_configfile\n");
We do the same in dhcp6_parse_options(). Please, factor out a common function to avoid code duplication.
I would prefer to keep these seperate for several reasons:
- our DHCP server team has asked for the DHCP6 "pxe config file" parsing
to change. I attempted to add to upstream here: https://lore.kernel.org/u-boot/20230725231329.5653-1-seanedmond@linux.micros.... I will attempt to submitted that patch again
- PXE config file isn't standardized yet for DHCPv6 (the current
implementation was a proposal from our DHCP server team)
- LWIP will eventually superceed bootp.c in u-boot, but we'll probably
be keeping dhcpv6.c for a bit (keeping the duplicate code will make the migration easier)
Best regards
Heinrich
+ } + break; default: #if defined(CONFIG_BOOTP_VENDOREX) if (dhcp_vendorex_proc(popt))