dhcpv4: use iovec for message and serverid

Start converting options over to an iovec based solution.

Also change the name of "type" in struct dhcpv4_option, both the DHCPv4 and
DHCPv6 RFCs call these "option codes", not types.

Signed-off-by: David Härdeman <[email protected]>
Link: https://github.com/openwrt/odhcpd/pull/278
Signed-off-by: Álvaro Fernández Rojas <[email protected]>

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index ced39f51927da4bdac17bc49d1d99bd48b9f3d88..7201c4a6ea9607c1cb450674de94f6ab8774ebaf 100644 (file)
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -619,6 +619,8 @@ static void dhcpv4_set_dest_addr(const struct interface *iface,
 
 enum {
        IOV_HEADER = 0,
+       IOV_MESSAGE,
+       IOV_SERVERID,
        IOV_END,
        IOV_TOTAL
 };
@@ -652,11 +654,22 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
                .siaddr = iface->dhcpv4_local,
                .cookie = htonl(DHCPV4_MAGIC_COOKIE),
        };
-       uint8_t reply_msg = DHCPV4_MSG_ACK;
+       struct dhcpv4_option_u8 reply_msg = {
+               .code = DHCPV4_OPT_MESSAGE,
+               .len = sizeof(uint8_t),
+               .data = DHCPV4_MSG_ACK,
+       };
+       struct dhcpv4_option_u32 reply_serverid = {
+               .code = DHCPV4_OPT_SERVERID,
+               .len = sizeof(struct in_addr),
+               .data = iface->dhcpv4_local.s_addr,
+       };
        uint8_t reply_end = DHCPV4_OPT_END;
 
        struct iovec iov[IOV_TOTAL] = {
                [IOV_HEADER] = { &reply, 0 },
+               [IOV_MESSAGE] = { &reply_msg, sizeof(reply_msg) },
+               [IOV_SERVERID] = { &reply_serverid, sizeof(reply_serverid) },
                [IOV_END] = { &reply_end, sizeof(reply_end) },
        };
 
@@ -665,7 +678,6 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
        uint8_t *cursor = reply.options;
        bool incl_fr_opt = false;
        struct dhcp_assignment *a = NULL;
-       uint32_t serverid = iface->dhcpv4_local.s_addr;
        uint32_t fr_serverid = INADDR_ANY;
 
        if (iface->dhcpv4 == MODE_DISABLED)
@@ -688,7 +700,7 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 
        struct dhcpv4_option *opt;
        dhcpv4_for_each_option(req->options, (uint8_t *)data + len, opt) {
-               switch (opt->type) {
+               switch (opt->code) {
                case DHCPV4_OPT_PAD:
                        break;
                case DHCPV4_OPT_HOSTNAME:
@@ -765,18 +777,18 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
        case DHCPV4_MSG_DISCOVER:
                if (!a)
                        return;
-               reply_msg = DHCPV4_MSG_OFFER;
+               reply_msg.data = DHCPV4_MSG_OFFER;
                break;
 
        case DHCPV4_MSG_REQUEST:
                if (!a) {
-                       reply_msg = DHCPV4_MSG_NAK;
+                       reply_msg.data = DHCPV4_MSG_NAK;
                        break;
                }
 
                if ((req_addr && req_addr != a->addr) ||
                    (req->ciaddr.s_addr && req->ciaddr.s_addr != a->addr)) {
-                       reply_msg = DHCPV4_MSG_NAK;
+                       reply_msg.data = DHCPV4_MSG_NAK;
                        /*
                         * DHCP client requested an IP which we can't offer to him. Probably the
                         * client changed the network or the network has been changed. The reply
@@ -792,7 +804,7 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
                         *
                         */
                        if (fr_serverid)
-                               serverid = fr_serverid;
+                               reply_serverid.data = fr_serverid;
 
                        if (req->ciaddr.s_addr &&
                                        ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
@@ -807,9 +819,6 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
                return;
        }
 
-       dhcpv4_put(&reply, &cursor, DHCPV4_OPT_MESSAGE, 1, &reply_msg);
-       dhcpv4_put(&reply, &cursor, DHCPV4_OPT_SERVERID, 4, &serverid);
-
        if (a) {
                uint32_t val;
 
@@ -963,24 +972,24 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
                }
        }
 
-       dhcpv4_set_dest_addr(iface, reply_msg, req, &reply, src_addr, &dest_addr);
+       dhcpv4_set_dest_addr(iface, reply_msg.data, req, &reply, src_addr, &dest_addr);
 
        iov[IOV_HEADER].iov_len = PACKET_SIZE(&reply, cursor);
 
        if (send_reply(iov, ARRAY_SIZE(iov), (struct sockaddr *)&dest_addr, sizeof(dest_addr), opaque) < 0)
                error("Failed to send %s to %s - %s: %m",
-                     dhcpv4_msg_to_string(reply_msg),
+                     dhcpv4_msg_to_string(reply_msg.data),
                      dest_addr.sin_addr.s_addr == INADDR_BROADCAST ?
                      "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
                      inet_ntoa(dest_addr.sin_addr));
        else
                error("Sent %s to %s - %s",
-                     dhcpv4_msg_to_string(reply_msg),
+                     dhcpv4_msg_to_string(reply_msg.data),
                      dest_addr.sin_addr.s_addr == INADDR_BROADCAST ?
                      "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
                      inet_ntoa(dest_addr.sin_addr));
 
-       if (reply_msg == DHCPV4_MSG_ACK && a)
+       if (reply_msg.data == DHCPV4_MSG_ACK && a)
                ubus_bcast_dhcp_event("dhcp.ack", req->chaddr,
                                      (struct in_addr *)&a->addr,
                                      a->hostname, iface->ifname);

diff --git a/src/dhcpv4.h b/src/dhcpv4.h
index d6c30408e4642c6e54676aae6a7fb3e716f46021..f96e5bf4169e362223062a74586ce00bf22e8f23 100644 (file)
--- a/src/dhcpv4.h
+++ b/src/dhcpv4.h
@@ -136,11 +136,23 @@ enum dhcpv4_auth_rkap_ai_type {
 };
 
 struct dhcpv4_option {
-       uint8_t type;
+       uint8_t code;
        uint8_t len;
        uint8_t data[];
 };
 
+struct dhcpv4_option_u8 {
+       uint8_t code;
+       uint8_t len;
+       uint8_t data;
+};
+
+struct dhcpv4_option_u32 {
+       uint8_t code;
+       uint8_t len;
+       uint32_t data;
+};
+
 /* DNR */
 struct dhcpv4_dnr {
        uint16_t len;