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-rw-r--r--slirp/dhcpv6.c209
1 files changed, 209 insertions, 0 deletions
diff --git a/slirp/dhcpv6.c b/slirp/dhcpv6.c
new file mode 100644
index 0000000000..02c51c7756
--- /dev/null
+++ b/slirp/dhcpv6.c
@@ -0,0 +1,209 @@
+/*
+ * SLIRP stateless DHCPv6
+ *
+ * We only support stateless DHCPv6, e.g. for network booting.
+ * See RFC 3315, RFC 3736, RFC 3646 and RFC 5970 for details.
+ *
+ * Copyright 2016 Thomas Huth, Red Hat 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; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "slirp.h"
+#include "dhcpv6.h"
+
+/* DHCPv6 message types */
+#define MSGTYPE_REPLY 7
+#define MSGTYPE_INFO_REQUEST 11
+
+/* DHCPv6 option types */
+#define OPTION_CLIENTID 1
+#define OPTION_IAADDR 5
+#define OPTION_ORO 6
+#define OPTION_DNS_SERVERS 23
+#define OPTION_BOOTFILE_URL 59
+
+struct requested_infos {
+ uint8_t *client_id;
+ int client_id_len;
+ bool want_dns;
+ bool want_boot_url;
+};
+
+/**
+ * Analyze the info request message sent by the client to see what data it
+ * provided and what it wants to have. The information is gathered in the
+ * "requested_infos" struct. Note that client_id (if provided) points into
+ * the odata region, thus the caller must keep odata valid as long as it
+ * needs to access the requested_infos struct.
+ */
+static int dhcpv6_parse_info_request(uint8_t *odata, int olen,
+ struct requested_infos *ri)
+{
+ int i, req_opt;
+
+ while (olen > 4) {
+ /* Parse one option */
+ int option = odata[0] << 8 | odata[1];
+ int len = odata[2] << 8 | odata[3];
+
+ if (len + 4 > olen) {
+ qemu_log_mask(LOG_GUEST_ERROR, "Guest sent bad DHCPv6 packet!\n");
+ return -E2BIG;
+ }
+
+ switch (option) {
+ case OPTION_IAADDR:
+ /* According to RFC3315, we must discard requests with IA option */
+ return -EINVAL;
+ case OPTION_CLIENTID:
+ if (len > 256) {
+ /* Avoid very long IDs which could cause problems later */
+ return -E2BIG;
+ }
+ ri->client_id = odata + 4;
+ ri->client_id_len = len;
+ break;
+ case OPTION_ORO: /* Option request option */
+ if (len & 1) {
+ return -EINVAL;
+ }
+ /* Check which options the client wants to have */
+ for (i = 0; i < len; i += 2) {
+ req_opt = odata[4 + i] << 8 | odata[4 + i + 1];
+ switch (req_opt) {
+ case OPTION_DNS_SERVERS:
+ ri->want_dns = true;
+ break;
+ case OPTION_BOOTFILE_URL:
+ ri->want_boot_url = true;
+ break;
+ default:
+ DEBUG_MISC((dfd, "dhcpv6: Unsupported option request %d\n",
+ req_opt));
+ }
+ }
+ break;
+ default:
+ DEBUG_MISC((dfd, "dhcpv6 info req: Unsupported option %d, len=%d\n",
+ option, len));
+ }
+
+ odata += len + 4;
+ olen -= len + 4;
+ }
+
+ return 0;
+}
+
+
+/**
+ * Handle information request messages
+ */
+static void dhcpv6_info_request(Slirp *slirp, struct sockaddr_in6 *srcsas,
+ uint32_t xid, uint8_t *odata, int olen)
+{
+ struct requested_infos ri = { NULL };
+ struct sockaddr_in6 sa6, da6;
+ struct mbuf *m;
+ uint8_t *resp;
+
+ if (dhcpv6_parse_info_request(odata, olen, &ri) < 0) {
+ return;
+ }
+
+ m = m_get(slirp);
+ if (!m) {
+ return;
+ }
+ memset(m->m_data, 0, m->m_size);
+ m->m_data += IF_MAXLINKHDR;
+ resp = (uint8_t *)m->m_data + sizeof(struct ip6) + sizeof(struct udphdr);
+
+ /* Fill in response */
+ *resp++ = MSGTYPE_REPLY;
+ *resp++ = (uint8_t)(xid >> 16);
+ *resp++ = (uint8_t)(xid >> 8);
+ *resp++ = (uint8_t)xid;
+
+ if (ri.client_id) {
+ *resp++ = OPTION_CLIENTID >> 8; /* option-code high byte */
+ *resp++ = OPTION_CLIENTID; /* option-code low byte */
+ *resp++ = ri.client_id_len >> 8; /* option-len high byte */
+ *resp++ = ri.client_id_len; /* option-len low byte */
+ memcpy(resp, ri.client_id, ri.client_id_len);
+ resp += ri.client_id_len;
+ }
+ if (ri.want_dns) {
+ *resp++ = OPTION_DNS_SERVERS >> 8; /* option-code high byte */
+ *resp++ = OPTION_DNS_SERVERS; /* option-code low byte */
+ *resp++ = 0; /* option-len high byte */
+ *resp++ = 16; /* option-len low byte */
+ memcpy(resp, &slirp->vnameserver_addr6, 16);
+ resp += 16;
+ }
+ if (ri.want_boot_url) {
+ uint8_t *sa = slirp->vhost_addr6.s6_addr;
+ int slen, smaxlen;
+
+ *resp++ = OPTION_BOOTFILE_URL >> 8; /* option-code high byte */
+ *resp++ = OPTION_BOOTFILE_URL; /* option-code low byte */
+ smaxlen = (uint8_t *)m->m_data + IF_MTU - (resp + 2);
+ slen = snprintf((char *)resp + 2, smaxlen,
+ "tftp://[%02x%02x:%02x%02x:%02x%02x:%02x%02x:"
+ "%02x%02x:%02x%02x:%02x%02x:%02x%02x]/%s",
+ sa[0], sa[1], sa[2], sa[3], sa[4], sa[5], sa[6], sa[7],
+ sa[8], sa[9], sa[10], sa[11], sa[12], sa[13], sa[14],
+ sa[15], slirp->bootp_filename);
+ slen = min(slen, smaxlen);
+ *resp++ = slen >> 8; /* option-len high byte */
+ *resp++ = slen; /* option-len low byte */
+ resp += slen;
+ }
+
+ sa6.sin6_addr = slirp->vhost_addr6;
+ sa6.sin6_port = DHCPV6_SERVER_PORT;
+ da6.sin6_addr = srcsas->sin6_addr;
+ da6.sin6_port = srcsas->sin6_port;
+ m->m_data += sizeof(struct ip6) + sizeof(struct udphdr);
+ m->m_len = resp - (uint8_t *)m->m_data;
+ udp6_output(NULL, m, &sa6, &da6);
+}
+
+/**
+ * Handle DHCPv6 messages sent by the client
+ */
+void dhcpv6_input(struct sockaddr_in6 *srcsas, struct mbuf *m)
+{
+ uint8_t *data = (uint8_t *)m->m_data + sizeof(struct udphdr);
+ int data_len = m->m_len - sizeof(struct udphdr);
+ uint32_t xid;
+
+ if (data_len < 4) {
+ return;
+ }
+
+ xid = ntohl(*(uint32_t *)data) & 0xffffff;
+
+ switch (data[0]) {
+ case MSGTYPE_INFO_REQUEST:
+ dhcpv6_info_request(m->slirp, srcsas, xid, &data[4], data_len - 4);
+ break;
+ default:
+ DEBUG_MISC((dfd, "dhcpv6_input: Unsupported message type 0x%x\n",
+ data[0]));
+ }
+}