shithub: plan9front

Download patch

ref: a89bee73739384c02c9d2caa82a0f780e3c25345
parent: d9bf5d074dccde7bc66d6c19565da9e5aeb5c7c5
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Sun Apr 11 14:20:41 EDT 2021

ip/dhcpd: work around raspberry pi pxe firmware by providing dhcp option 66

The raspberry pi 4 PXE firmware insists on finding the tftp
server address by parsing dhcp option 66 as an ip address
string.

--- a/sys/src/cmd/ip/dhcpd/dhcpd.c	Sun Apr 11 14:18:03 2021
+++ b/sys/src/cmd/ip/dhcpd/dhcpd.c	Sun Apr 11 14:20:41 2021
@@ -1136,8 +1136,7 @@
 	uchar *addrs[8];
 	uchar *op, *omax;
 	uchar x[nelem(addrs)*IPaddrlen], vopts[Maxoptlen];
-	char *p;
-	char *attr[100], **a;
+	char ip4str[16], *p, *attr[100], **a;
 	Ndbtuple *t;
 	Iplifc *lifc;
 
@@ -1278,6 +1277,21 @@
 			break;
 		case OBttl:
 			byteopt(rp, OBttl, 255);
+			break;
+
+		case ODtftpserver:
+			/* 
+			 * This option actually should contain a hostname, BUT:
+			 * It appears that Rpi4 PXE firmware ignores the siaddr
+			 * and instead insists on this (DHCP option 66) to contain
+			 * the IP address string of the TFTP server.
+			 */
+			snprint(ip4str, sizeof(ip4str), "%V", rp->bp->siaddr);
+			stringopt(rp, ODtftpserver, ip4str);
+			break;
+		case ODbootfile:
+			if(*rp->bp->file)
+				stringopt(rp, ODbootfile, rp->bp->file);
 			break;
 		}