| /* |
| * 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])); |
| } |
| } |