From 604f882083472b515342c43790eb252dd0e9a18b Mon Sep 17 00:00:00 2001
From: Rakesh Ranjan <rakesh@chelsio.com>
Date: Mon, 16 Nov 2009 19:10:00 +0530
Subject: [PATCH 2/2] dhcp handler for libiscsi to support dhcp provisioning for offload capable cards.
This module contains a compact dhcp handler to support dhcp based provisioning for
offload capable cards.
Signed-off-by: Rakesh Ranjan <rakesh@chelsio.com>
---
drivers/scsi/Makefile | 2 +-
drivers/scsi/libiscsi_ipconfig.c | 466 ++++++++++++++++++++++++++++++++++++++
2 files changed, 467 insertions(+), 1 deletions(-)
create mode 100644 drivers/scsi/libiscsi_ipconfig.c
@@ -129,7 +129,7 @@ obj-$(CONFIG_SCSI_HPTIOP) += hptiop.o
obj-$(CONFIG_SCSI_STEX) += stex.o
obj-$(CONFIG_SCSI_MVSAS) += mvsas/
obj-$(CONFIG_PS3_ROM) += ps3rom.o
-obj-$(CONFIG_SCSI_CXGB3_ISCSI) += libiscsi.o libiscsi_tcp.o cxgb3i/
+obj-$(CONFIG_SCSI_CXGB3_ISCSI) += libiscsi.o libiscsi_ipconfig.o libiscsi_tcp.o cxgb3i/
obj-$(CONFIG_SCSI_BNX2_ISCSI) += libiscsi.o bnx2i/
obj-$(CONFIG_BE2ISCSI) += libiscsi.o be2iscsi/
obj-$(CONFIG_SCSI_PMCRAID) += pmcraid.o
new file mode 100644
@@ -0,0 +1,466 @@
+/* libiscsi_ipconfig.c: libiscsi dhcp client.
+ *
+ * Copyright (c) 2009 Chelsio Communications, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.
+ *
+ * Written by: Rakesh Ranjan (rakesh@chelsio.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/in.h>
+#include <linux/delay.h>
+#include <linux/if_arp.h>
+#include <net/ip.h>
+#include <scsi/iscsi_if.h>
+#include <scsi/libiscsi.h>
+
+#define DHCP_REQUEST 1
+#define DHCP_REPLY 2
+#define DHCP_HTYPE_ETHERNET 1
+#define DHCP_HLEN_ETHERNET 6
+#define DHCP_MSG_LEN 236
+
+#define DHCPC_SERVER_PORT 67
+#define DHCPC_CLIENT_PORT 68
+
+/* DHCP message types */
+#define DHCPDISCOVER 1
+#define DHCPOFFER 2
+#define DHCPREQUEST 3
+#define DHCPDECLINE 4
+#define DHCPACK 5
+#define DHCPNAK 6
+#define DHCPRELEASE 7
+#define DHCPINFORM 8
+
+/* DHCP options */
+#define DHCP_OPTION_SUBNET_MASK 1
+#define DHCP_OPTION_ROUTER 3
+#define DHCP_OPTION_DNS_SERVER 6
+#define DHCP_OPTION_MTU 26
+#define DHCP_OPTION_REQ_IPADDR 50
+#define DHCP_OPTION_LEASE_TIME 51
+#define DHCP_OPTION_MSG_TYPE 53
+#define DHCP_OPTION_SERVER_ID 54
+#define DHCP_OPTION_REQ_LIST 55
+#define DHCP_OPTION_VCID 60
+#define DHCP_OPTION_END 255
+
+enum {
+ STATE_INIT = 0,
+ STATE_SENDING,
+ STATE_OFFER_REC,
+ STATE_CONFIG_REC,
+};
+
+struct dhcp_pkt {
+ struct iphdr iph;
+ struct udphdr udph;
+ u8 op;
+ u8 htype;
+ u8 hlen;
+ u8 hops;
+ __be32 xid;
+ __be16 secs;
+ __be16 flags;
+ __be32 cipaddr;
+ __be32 yipaddr;
+ __be32 sipaddr;
+ __be32 ripaddr;
+ u8 chwaddr[16];
+ u8 sname[64];
+ u8 bfile[128];
+ u8 options[312];
+};
+
+
+static struct dhcp_client_state {
+ struct sk_buff *skb;
+ struct dhcp_pkt *pkt;
+ struct net_device *ndev;
+ struct list_head list;
+ struct dhcp_info dinfo;
+
+ volatile __u8 state;
+ __be32 xid;
+
+} client_state;
+
+static DEFINE_SPINLOCK(rcv_lock);
+
+static const char *RFC2132_VENDOR_CLASS_ID = "libiscsi client";
+
+static const u8 magic_cookie[4] = { 99, 130, 83, 99 };
+
+static inline u8 *add_msg_type(u8 *optptr, u8 type)
+{
+ *optptr++ = DHCP_OPTION_MSG_TYPE;
+ *optptr++ = 1;
+ *optptr++ = type;
+ return optptr;
+}
+
+static inline u8 *add_req_options(u8 *optptr)
+{
+ *optptr++ = DHCP_OPTION_REQ_LIST;
+ *optptr++ = 4;
+ *optptr++ = DHCP_OPTION_SUBNET_MASK;
+ *optptr++ = DHCP_OPTION_ROUTER;
+ *optptr++ = DHCP_OPTION_DNS_SERVER;
+ *optptr++ = DHCP_OPTION_MTU;
+ return optptr;
+}
+
+static inline u8 *add_vendor_cid(u8 *optptr)
+{
+ u8 len = strlen(RFC2132_VENDOR_CLASS_ID);
+ *optptr++ = DHCP_OPTION_VCID;
+ *optptr++ = len;
+ memcpy(optptr, RFC2132_VENDOR_CLASS_ID, len);
+ optptr += len;
+ return optptr;
+}
+
+static inline u8 *add_server_id(__be32 *sid, u8 *optptr)
+{
+ *optptr++ = DHCP_OPTION_SERVER_ID;
+ *optptr++ = 4;
+ memcpy(optptr, sid, 4);
+ return optptr + 4;
+}
+
+static inline u8 *add_req_ipaddr(__be32 *ip, u8 *optptr)
+{
+ *optptr++ = DHCP_OPTION_REQ_IPADDR;
+ *optptr++ = 4;
+ memcpy(optptr, ip, 4);
+ return optptr + 4;
+}
+
+static inline u8 *add_end(u8 *optptr)
+{
+ *optptr++ = DHCP_OPTION_END;
+ return optptr;
+}
+
+static void
+libiscsi_process_dhcp_opts(struct dhcp_client_state *client, u8 *optptr,
+ int len)
+{
+ u8 *end = optptr + len;
+ u8 type = 0;
+
+ while (optptr < end) {
+ switch (*optptr) {
+ case DHCP_OPTION_SUBNET_MASK:
+ memcpy(&client->dinfo.netmask, optptr + 2, 4);
+ break;
+ case DHCP_OPTION_ROUTER:
+ memcpy(&client->dinfo.gipaddr, optptr + 2, 4);
+ break;
+ case DHCP_OPTION_DNS_SERVER:
+ memcpy(&client->dinfo.dnsaddr, optptr + 2, 4);
+ break;
+ case DHCP_OPTION_MSG_TYPE:
+ type = *(optptr + 2);
+ if (type == DHCPOFFER)
+ client->state = STATE_OFFER_REC;
+ else if (type == DHCPACK)
+ client->state = STATE_CONFIG_REC;
+ break;
+ case DHCP_OPTION_SERVER_ID:
+ memcpy(&client->dinfo.serverid, optptr + 2, 4);
+ break;
+ case DHCP_OPTION_LEASE_TIME:
+ memcpy(&client->dinfo.ltime, optptr + 2, 4);
+ break;
+ case DHCP_OPTION_END:
+ break;
+ }
+
+ optptr += optptr[1] + 2;
+ }
+}
+
+static void
+libiscsi_process_dhcp_pack(struct dhcp_client_state *client,
+ struct dhcp_pkt *pkt)
+{
+ u8 *start, *end;
+ int opt_len;
+
+ start = &pkt->options[4];
+ end = (u8 *) pkt + ntohs(pkt->iph.tot_len);
+ opt_len = end - start;
+
+ if (pkt->op == DHCP_REPLY &&
+ !memcmp(&pkt->xid, &client->xid, sizeof(client->xid)) &&
+ !memcmp(pkt->chwaddr, client->dinfo.mac_addr, pkt->hlen)) {
+ memcpy(&client->dinfo.ipaddr, &pkt->yipaddr, 4);
+ libiscsi_process_dhcp_opts(client, start, opt_len);
+ }
+}
+
+static int
+libiscsi_ipconfig_send(struct dhcp_client_state *client)
+{
+ int rc = 0;
+ struct sk_buff *lskb = client->skb;
+
+ lskb->dev = client->ndev;
+ lskb->protocol = htons(ETH_P_IP);
+
+ dev_hard_header(lskb, client->ndev, ntohs(lskb->protocol),
+ client->ndev->broadcast,
+ client->dinfo.mac_addr, lskb->len);
+ rc = dev_queue_xmit(lskb);
+
+ return rc;
+}
+
+int
+libiscsi_ipconfig_recv(struct net_device *ndev, struct sk_buff *skb)
+{
+ struct iphdr *iph;
+ struct udphdr *udph;
+ struct ethhdr *eh;
+ struct dhcp_pkt *pkt;
+ struct sk_buff *pskb;
+ int len, opts_len;
+ struct dhcp_client_state *client;
+ int rc = 0;
+
+
+ client = &client_state;
+
+ if (unlikely(client->state == STATE_INIT))
+ goto out;
+
+ if (skb->pkt_type != PACKET_OTHERHOST)
+ goto out;
+
+ pskb = skb_copy(skb, GFP_ATOMIC);
+ if (!pskb) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ eh = eth_hdr(pskb);
+ if (!is_valid_ether_addr(eh->h_dest))
+ goto drop;
+
+ if (compare_ether_addr(eh->h_dest, client->dinfo.mac_addr))
+ goto drop;
+
+ if (!pskb_may_pull(pskb, sizeof(struct iphdr) + sizeof(struct udphdr)))
+ goto drop;
+
+
+ skb_reset_network_header(pskb);
+ pkt = (struct dhcp_pkt *) skb_network_header(pskb);
+ iph = &pkt->iph;
+
+ if (iph->ihl != 5 || iph->version != 4 || iph->protocol != IPPROTO_UDP)
+ goto drop;
+
+ if (iph->frag_off & htons(IP_OFFSET | IP_MF))
+ goto drop;
+
+ if (skb->len < ntohs(iph->tot_len))
+ goto drop;
+
+ if (ip_fast_csum((u8 *)iph, iph->ihl))
+ goto drop;
+
+ udph = &pkt->udph;
+ if (udph->source != htons(67) || udph->dest != htons(68))
+ goto drop;
+
+ if (ntohs(iph->tot_len) < ntohs(udph->len) + sizeof(struct iphdr))
+ goto drop;
+
+ len = ntohs(udph->len) - sizeof(struct udphdr);
+ opts_len = len - (sizeof(*pkt) -
+ sizeof(struct iphdr) -
+ sizeof(struct udphdr) -
+ sizeof(pkt->options));
+ if (opts_len < 0)
+ goto drop;
+
+ if (memcmp(pkt->options, magic_cookie, 4))
+ goto drop;
+
+ spin_lock(&rcv_lock);
+
+ libiscsi_process_dhcp_pack(client, pkt);
+
+ spin_unlock(&rcv_lock);
+
+drop:
+ kfree(pskb);
+out:
+ return rc;
+}
+EXPORT_SYMBOL(libiscsi_ipconfig_recv);
+
+static int
+libiscsi_create_dhcp_msg(struct dhcp_client_state *client)
+{
+ struct iphdr *iph;
+ struct udphdr *udph;
+ struct sk_buff *skb;
+ struct dhcp_pkt *pkt;
+ int rc = 0;
+
+ skb = alloc_skb(sizeof(*pkt) +
+ LL_ALLOCATED_SPACE(client->ndev) + 15,
+ GFP_KERNEL);
+ if (!skb) {
+ rc = -ENOMEM;
+ return rc;
+ }
+
+ client->skb = skb;
+ skb_reserve(skb, LL_RESERVED_SPACE(client->ndev));
+
+ pkt = (struct dhcp_pkt *) skb_put(skb, sizeof(*pkt));
+ BUG_ON(!pkt);
+ client->pkt = pkt;
+ memset(pkt, 0, sizeof(*pkt));
+
+ skb_reset_network_header(skb);
+
+ /* construct IP header */
+ iph = &pkt->iph;
+ iph->version = 4;
+ iph->ihl = 5;
+ iph->tot_len = htons(sizeof(struct dhcp_pkt));
+ iph->frag_off = htons(IP_DF);
+ iph->ttl = 64;
+ iph->protocol = IPPROTO_UDP;
+ iph->daddr = htonl(INADDR_BROADCAST);
+ iph->check = ip_fast_csum((u8 *) iph, iph->ihl);
+
+ /* Construct UDP header */
+ udph = &pkt->udph;
+ udph->source = htons(DHCPC_CLIENT_PORT);
+ udph->dest = htons(DHCPC_SERVER_PORT);
+ udph->len = htons(sizeof(struct dhcp_pkt) - sizeof(struct iphdr));
+
+ pkt->op = DHCP_REQUEST;
+ pkt->htype = DHCP_HTYPE_ETHERNET;
+ pkt->hlen = ETH_ALEN;
+
+ memcpy(pkt->chwaddr, client->dinfo.mac_addr, ETH_ALEN);
+ pkt->secs = htons(jiffies / HZ);
+ pkt->xid = client->xid;
+
+ memcpy(pkt->options, magic_cookie, sizeof(magic_cookie));
+
+ return rc;
+}
+
+static int libiscsi_send_dhcp_request(struct dhcp_client_state *client)
+{
+ int rc = 0;
+ u8 *end;
+
+ rc = libiscsi_create_dhcp_msg(client);
+ if (rc)
+ return rc;
+
+ end = add_msg_type(&client->pkt->options[4], DHCPREQUEST);
+ end = add_server_id(&client->dinfo.serverid, end);
+ end = add_req_ipaddr(&client->dinfo.ipaddr, end);
+ end = add_vendor_cid(end);
+ end = add_end(end);
+
+ rc = libiscsi_ipconfig_send(client);
+
+ return rc;
+}
+
+static int libiscsi_send_dhcp_discover(struct dhcp_client_state *client)
+{
+ int rc = 0;
+ u8 *end;
+
+ rc = libiscsi_create_dhcp_msg(client);
+ if (rc)
+ return rc;
+
+ end = add_msg_type(&client->pkt->options[4], DHCPDISCOVER);
+ end = add_req_options(end);
+ end = add_vendor_cid(end);
+ end = add_end(end);
+
+ client->state = STATE_SENDING;
+ rc = libiscsi_ipconfig_send(client);
+
+ return rc;
+}
+
+static void
+libiscsi_wait_for_pack(struct dhcp_client_state *client, u8 state)
+{
+ unsigned long tout, ntout;
+
+ get_random_bytes(&tout, sizeof(tout));
+ tout = (tout % (unsigned)HZ) + (HZ * 2);
+
+ ntout = jiffies + tout;
+ while (time_before(jiffies, ntout) && (client->state != state))
+ schedule_timeout_uninterruptible(1);
+}
+
+int libiscsi_do_ipconf(struct net_device *ndev, struct dhcp_info *dinfo)
+{
+ int rc = 0;
+ int retry;
+ struct dhcp_client_state *client;
+ retry = 2;
+
+ client = &client_state;
+ client->dinfo.mac_addr = dinfo->mac_addr;
+ client->ndev = ndev;
+ client->state = STATE_INIT;
+
+ /* show time */
+ for (;;) {
+ get_random_bytes(&client->xid, sizeof(__be32));
+ libiscsi_send_dhcp_discover(client);
+ libiscsi_wait_for_pack(client, STATE_OFFER_REC);
+
+ if (client->state == STATE_OFFER_REC) {
+ libiscsi_send_dhcp_request(client);
+ libiscsi_wait_for_pack(client, STATE_CONFIG_REC);
+ if (client->state == STATE_CONFIG_REC) {
+ dinfo->ipaddr = client->dinfo.ipaddr;
+ dinfo->netmask = client->dinfo.netmask;
+ dinfo->ltime = client->dinfo.ltime;
+ client->state = STATE_INIT;
+ break;
+ }
+ }
+
+ if (!--retry) {
+ rc = -ENETUNREACH;
+ break;
+ }
+ }
+
+ return rc;
+}
+EXPORT_SYMBOL(libiscsi_do_ipconf);
+
+MODULE_AUTHOR("Rakesh Ranjan");
+MODULE_DESCRIPTION("iSCSI ipconfig functions");
+MODULE_LICENSE("GPL");
--
1.6.0.6