diff options
Diffstat (limited to 'dhcp.c')
| -rw-r--r-- | dhcp.c | 72 |
1 files changed, 51 insertions, 21 deletions
@@ -36,9 +36,9 @@ /** * struct opt - DHCP option * @sent: Convenience flag, set while filling replies - * @slen: Length of option defined for server + * @slen: Length of option defined for server, -1 if not going to be sent * @s: Option payload from server - * @clen: Length of option received from client + * @clen: Length of option received from client, -1 if not received * @c: Option payload from client */ struct opt { @@ -68,6 +68,11 @@ static struct opt opts[255]; */ void dhcp_init(void) { + int i; + + for (i = 0; i < ARRAY_SIZE(opts); i++) + opts[i].slen = -1; + opts[1] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, }; /* Mask */ opts[3] = (struct opt) { 0, 4, { 0 }, 0, { 0 }, }; /* Router */ opts[51] = (struct opt) { 0, 4, { 0xff, @@ -107,6 +112,8 @@ struct msg { uint32_t xid; uint16_t secs; uint16_t flags; +#define FLAG_BROADCAST htons_constant(0x8000) + uint32_t ciaddr; struct in_addr yiaddr; uint32_t siaddr; @@ -154,17 +161,17 @@ static int fill(struct msg *m) * option 53 at the beginning of the list. * Put it there explicitly, unless requested via option 55. */ - if (!memchr(opts[55].c, 53, opts[55].clen)) + if (opts[55].clen > 0 && !memchr(opts[55].c, 53, opts[55].clen)) fill_one(m, 53, &offset); for (i = 0; i < opts[55].clen; i++) { o = opts[55].c[i]; - if (opts[o].slen) + if (opts[o].slen != -1) fill_one(m, o, &offset); } for (o = 0; o < 255; o++) { - if (opts[o].slen && !opts[o].sent) + if (opts[o].slen != -1 && !opts[o].sent) fill_one(m, o, &offset); } @@ -264,6 +271,9 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len) ".\xc0"); } } + + if (!opts[119].slen) + opts[119].slen = -1; } /** @@ -276,10 +286,11 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len) int dhcp(const struct ctx *c, const struct pool *p) { size_t mlen, dlen, offset = 0, opt_len, opt_off = 0; + char macstr[ETH_ADDRSTRLEN]; + struct in_addr mask, dst; const struct ethhdr *eh; const struct iphdr *iph; const struct udphdr *uh; - struct in_addr mask; unsigned int i; struct msg *m; @@ -312,6 +323,9 @@ int dhcp(const struct ctx *c, const struct pool *p) offset += offsetof(struct msg, o); + for (i = 0; i < ARRAY_SIZE(opts); i++) + opts[i].clen = -1; + while (opt_off + 2 < opt_len) { const uint8_t *olen, *val; uint8_t *type; @@ -330,36 +344,44 @@ int dhcp(const struct ctx *c, const struct pool *p) opt_off += *olen + 2; } - if (opts[53].c[0] == DHCPDISCOVER) { - info("DHCP: offer to discover"); - opts[53].s[0] = DHCPOFFER; - } else if (opts[53].c[0] == DHCPREQUEST || !opts[53].clen) { - info("%s: ack to request", opts[53].clen ? "DHCP" : "BOOTP"); + opts[80].slen = -1; + if (opts[53].clen > 0 && opts[53].c[0] == DHCPDISCOVER) { + if (opts[80].clen == -1) { + info("DHCP: offer to discover"); + opts[53].s[0] = DHCPOFFER; + } else { + info("DHCP: ack to discover (Rapid Commit)"); + opts[53].s[0] = DHCPACK; + opts[80].slen = 0; + } + } else if (opts[53].clen <= 0 || opts[53].c[0] == DHCPREQUEST) { + info("%s: ack to request", /* DHCP needs a valid message type */ + (opts[53].clen <= 0) ? "BOOTP" : "DHCP"); opts[53].s[0] = DHCPACK; } else { return -1; } - info(" from %02x:%02x:%02x:%02x:%02x:%02x", - m->chaddr[0], m->chaddr[1], m->chaddr[2], - m->chaddr[3], m->chaddr[4], m->chaddr[5]); + info(" from %s", eth_ntop(m->chaddr, macstr, sizeof(macstr))); m->yiaddr = c->ip4.addr; mask.s_addr = htonl(0xffffffff << (32 - c->ip4.prefix_len)); - memcpy(opts[1].s, &mask, sizeof(mask)); - memcpy(opts[3].s, &c->ip4.gw, sizeof(c->ip4.gw)); - memcpy(opts[54].s, &c->ip4.gw, sizeof(c->ip4.gw)); + memcpy(opts[1].s, &mask, sizeof(mask)); + memcpy(opts[3].s, &c->ip4.guest_gw, sizeof(c->ip4.guest_gw)); + memcpy(opts[54].s, &c->ip4.our_tap_addr, sizeof(c->ip4.our_tap_addr)); /* If the gateway is not on the assigned subnet, send an option 121 * (Classless Static Routing) adding a dummy route to it. */ if ((c->ip4.addr.s_addr & mask.s_addr) - != (c->ip4.gw.s_addr & mask.s_addr)) { + != (c->ip4.guest_gw.s_addr & mask.s_addr)) { /* a.b.c.d/32:0.0.0.0, 0:a.b.c.d */ opts[121].slen = 14; opts[121].s[0] = 32; - memcpy(opts[121].s + 1, &c->ip4.gw, sizeof(c->ip4.gw)); - memcpy(opts[121].s + 10, &c->ip4.gw, sizeof(c->ip4.gw)); + memcpy(opts[121].s + 1, + &c->ip4.guest_gw, sizeof(c->ip4.guest_gw)); + memcpy(opts[121].s + 10, + &c->ip4.guest_gw, sizeof(c->ip4.guest_gw)); } if (c->mtu != -1) { @@ -373,12 +395,20 @@ int dhcp(const struct ctx *c, const struct pool *p) ((struct in_addr *)opts[6].s)[i] = c->ip4.dns[i]; opts[6].slen += sizeof(uint32_t); } + if (!opts[6].slen) + opts[6].slen = -1; if (!c->no_dhcp_dns_search) opt_set_dns_search(c, sizeof(m->o)); dlen = offsetof(struct msg, o) + fill(m); - tap_udp4_send(c, c->ip4.gw, 67, c->ip4.addr, 68, m, dlen); + + if (m->flags & FLAG_BROADCAST) + dst = in4addr_broadcast; + else + dst = c->ip4.addr; + + tap_udp4_send(c, c->ip4.our_tap_addr, 67, dst, 68, m, dlen); return 1; } |