diff --git a/firmware/include/arp.h b/firmware/include/arp.h
index a27b221..f073b01 100644
--- a/firmware/include/arp.h
+++ b/firmware/include/arp.h
@@ -1,5 +1,4 @@
 #pragma once
-#include <functional>
 #include <span>
 #include "eth.h"
 #include "ipv4.h"
@@ -21,7 +20,6 @@ struct __attribute__((packed)) header {
 static_assert(sizeof(header) == 28);
 
 void handle(std::span<const uint8_t> frame, span_writer& tx,
-            eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-            std::function<void(std::span<const uint8_t>)> send_raw);
+            eth::mac_addr our_mac, ipv4::ip4_addr our_ip);
 
 } // namespace arp
diff --git a/firmware/include/icmp.h b/firmware/include/icmp.h
index f92ca8e..4946587 100644
--- a/firmware/include/icmp.h
+++ b/firmware/include/icmp.h
@@ -1,6 +1,5 @@
 #pragma once
 #include <cstdint>
-#include <functional>
 #include <span>
 #include "eth.h"
 #include "ipv4.h"
@@ -18,8 +17,7 @@ struct __attribute__((packed)) echo {
 static_assert(sizeof(echo) == 8);
 
 void handle(std::span<const uint8_t> frame, span_writer& tx,
-            eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-            std::function<void(std::span<const uint8_t>)> send_raw);
+            eth::mac_addr our_mac, ipv4::ip4_addr our_ip);
 
 template <typename Buf>
 void prepend_echo_request(Buf& buf,
diff --git a/firmware/include/igmp.h b/firmware/include/igmp.h
index fa8529f..c066e1a 100644
--- a/firmware/include/igmp.h
+++ b/firmware/include/igmp.h
@@ -1,6 +1,5 @@
 #pragma once
 #include <cstdint>
-#include <functional>
 #include <span>
 #include "eth.h"
 #include "ipv4.h"
@@ -24,15 +23,12 @@ bool is_member(const ipv4::ip4_addr& ip);
 bool is_member_mac(const eth::mac_addr& mac);
 
 void join(const ipv4::ip4_addr& group,
-          eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-          std::function<void(std::span<const uint8_t>)> send_raw);
+          eth::mac_addr our_mac, ipv4::ip4_addr our_ip);
 
-void send_all_reports(eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-                      std::function<void(std::span<const uint8_t>)> send_raw);
+void send_all_reports(eth::mac_addr our_mac, ipv4::ip4_addr our_ip);
 
 void handle(std::span<const uint8_t> frame, span_writer& tx,
-            eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-            std::function<void(std::span<const uint8_t>)> send_raw);
+            eth::mac_addr our_mac, ipv4::ip4_addr our_ip);
 
 template <typename Buf>
 void prepend_report(Buf& buf, const eth::mac_addr& src_mac, ipv4::ip4_addr src_ip,
diff --git a/firmware/include/ipv4.h b/firmware/include/ipv4.h
index 602b017..03f6b2b 100644
--- a/firmware/include/ipv4.h
+++ b/firmware/include/ipv4.h
@@ -58,7 +58,6 @@ void prepend(Buf& buf, const eth::mac_addr& dst_mac, const eth::mac_addr& src_ma
 
 void handle(std::span<const uint8_t> frame, span_writer& tx,
             eth::mac_addr our_mac, ip4_addr our_ip, ip4_addr subnet_broadcast,
-            std::function<void(std::span<const uint8_t>)> send_raw,
             std::function<void(std::span<const uint8_t>, span_writer&)> handle_udp);
 
 } // namespace ipv4
diff --git a/firmware/lib/arp.cpp b/firmware/lib/arp.cpp
index 1bafa43..02971b4 100644
--- a/firmware/lib/arp.cpp
+++ b/firmware/lib/arp.cpp
@@ -1,4 +1,5 @@
 #include "arp.h"
+#include "net.h"
 #include "parse_buffer.h"
 #include "prepend_buffer.h"
 
@@ -10,8 +11,7 @@ static constexpr uint16_t ARP_OP_REQUEST = __builtin_bswap16(1);
 static constexpr uint16_t ARP_OP_REPLY = __builtin_bswap16(2);
 
 void handle(std::span<const uint8_t> frame, span_writer& tx,
-            eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-            std::function<void(std::span<const uint8_t>)> send_raw) {
+            eth::mac_addr our_mac, ipv4::ip4_addr our_ip) {
     parse_buffer pb(frame);
     pb.consume<eth::header>();
     auto* arp_hdr = pb.consume<header>();
@@ -36,7 +36,7 @@ void handle(std::span<const uint8_t> frame, span_writer& tx,
     reply->tpa = arp_hdr->spa;
     eth::prepend(buf, arp_hdr->sha, our_mac, eth::ETH_ARP);
 
-    send_raw(buf.span());
+    net_send_raw(buf.span());
 }
 
 } // namespace arp
diff --git a/firmware/lib/dispatch.cpp b/firmware/lib/dispatch.cpp
index ae00e52..e141fe5 100644
--- a/firmware/lib/dispatch.cpp
+++ b/firmware/lib/dispatch.cpp
@@ -1,5 +1,4 @@
 #include "dispatch.h"
-#include <unordered_map>
 #include "pico/stdlib.h"
 #include "wire.h"
 #include "timer_queue.h"
@@ -12,7 +11,7 @@ static timer_queue timers;
 
 static void igmp_reannounce() {
     auto& ns = net_get_state();
-    igmp::send_all_reports(ns.mac, ns.ip, net_send_raw);
+    igmp::send_all_reports(ns.mac, ns.ip);
     dispatch_schedule_ms(60000, igmp_reannounce);
 }
 
@@ -33,7 +32,7 @@ bool dispatch_cancel_timer(timer_handle h) {
 }
 
 [[noreturn]] void dispatch_run(std::span<const handler_entry> handlers) {
-    std::unordered_map<int8_t, handler_fn> handler_map;
+    std::array<handler_fn, 128> handler_map{};
     for (auto& entry : handlers) {
         handler_map[entry.type_id] = entry.handle;
     }
@@ -41,13 +40,12 @@ bool dispatch_cancel_timer(timer_handle h) {
     static std::array<uint8_t, 4096> tx_buf;
 
     auto dispatch_msg = [&](const DecodedMessage& msg, send_fn send) {
-        auto it = handler_map.find(msg.type_id);
-        if (it == handler_map.end()) {
+        if (msg.type_id < 0 || !handler_map[msg.type_id]) {
             dlogf("dispatch: unknown type_id %d", msg.type_id);
             return;
         }
         responder resp{msg.message_id, std::move(send)};
-        it->second(resp, msg.payload);
+        handler_map[msg.type_id](resp, msg.payload);
     };
 
     net_set_handler([&](std::span<const uint8_t> payload,
diff --git a/firmware/lib/icmp.cpp b/firmware/lib/icmp.cpp
index 595b642..0fe864b 100644
--- a/firmware/lib/icmp.cpp
+++ b/firmware/lib/icmp.cpp
@@ -1,14 +1,14 @@
 #include "icmp.h"
 #include <cstring>
 #include "ipv4.h"
+#include "net.h"
 #include "parse_buffer.h"
 #include "prepend_buffer.h"
 
 namespace icmp {
 
 void handle(std::span<const uint8_t> frame, span_writer& tx,
-            eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-            std::function<void(std::span<const uint8_t>)> send_raw) {
+            eth::mac_addr our_mac, ipv4::ip4_addr our_ip) {
     parse_buffer pb(frame);
     auto* eth_hdr = pb.consume<eth::header>();
     auto* ip = pb.consume<ipv4::header>();
@@ -34,7 +34,7 @@ void handle(std::span<const uint8_t> frame, span_writer& tx,
     reply->checksum = ipv4::checksum(reply, icmp_len);
 
     ipv4::prepend(buf, eth_hdr->src, our_mac, our_ip, ip->src, 1, icmp_len);
-    send_raw(buf.span());
+    net_send_raw(buf.span());
 }
 
 bool parse_echo_reply(std::span<const uint8_t> frame, ipv4::ip4_addr& src_ip, uint16_t expected_id) {
diff --git a/firmware/lib/igmp.cpp b/firmware/lib/igmp.cpp
index c8aafd6..b8878cd 100644
--- a/firmware/lib/igmp.cpp
+++ b/firmware/lib/igmp.cpp
@@ -1,6 +1,7 @@
 #include "igmp.h"
 #include <vector>
 #include "ipv4.h"
+#include "net.h"
 #include "parse_buffer.h"
 #include "prepend_buffer.h"
 
@@ -34,31 +35,27 @@ bool is_member_mac(const eth::mac_addr& mac) {
 }
 
 static void send_report(const ipv4::ip4_addr& group,
-                         eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-                         std::function<void(std::span<const uint8_t>)> send_raw) {
+                         eth::mac_addr our_mac, ipv4::ip4_addr our_ip) {
     prepend_buffer<4096> buf;
     prepend_report(buf, our_mac, our_ip, group);
-    send_raw(buf.span());
+    net_send_raw(buf.span());
 }
 
 void join(const ipv4::ip4_addr& group,
-          eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-          std::function<void(std::span<const uint8_t>)> send_raw) {
+          eth::mac_addr our_mac, ipv4::ip4_addr our_ip) {
     for (auto& g : groups)
         if (g.ip == group) return;
     groups.push_back({group, mac_for_ip(group)});
-    send_report(group, our_mac, our_ip, send_raw);
+    send_report(group, our_mac, our_ip);
 }
 
-void send_all_reports(eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-                      std::function<void(std::span<const uint8_t>)> send_raw) {
+void send_all_reports(eth::mac_addr our_mac, ipv4::ip4_addr our_ip) {
     for (auto& g : groups)
-        send_report(g.ip, our_mac, our_ip, send_raw);
+        send_report(g.ip, our_mac, our_ip);
 }
 
 void handle(std::span<const uint8_t> frame, span_writer& tx,
-            eth::mac_addr our_mac, ipv4::ip4_addr our_ip,
-            std::function<void(std::span<const uint8_t>)> send_raw) {
+            eth::mac_addr our_mac, ipv4::ip4_addr our_ip) {
     parse_buffer pb(frame);
     pb.consume<eth::header>();
     auto* ip = pb.consume<ipv4::header>();
@@ -73,11 +70,11 @@ void handle(std::span<const uint8_t> frame, span_writer& tx,
 
     if (msg->group == ipv4::ip4_addr{0, 0, 0, 0}) {
         for (auto& g : groups)
-            send_report(g.ip, our_mac, our_ip, send_raw);
+            send_report(g.ip, our_mac, our_ip);
     } else {
         for (auto& g : groups) {
             if (g.ip == msg->group) {
-                send_report(g.ip, our_mac, our_ip, send_raw);
+                send_report(g.ip, our_mac, our_ip);
                 break;
             }
         }
diff --git a/firmware/lib/ipv4.cpp b/firmware/lib/ipv4.cpp
index 96ee2e0..b06282c 100644
--- a/firmware/lib/ipv4.cpp
+++ b/firmware/lib/ipv4.cpp
@@ -25,7 +25,6 @@ static bool ip_match(const ip4_addr& dst, const ip4_addr& our_ip, const ip4_addr
 
 void handle(std::span<const uint8_t> frame, span_writer& tx,
             eth::mac_addr our_mac, ip4_addr our_ip, ip4_addr subnet_broadcast,
-            std::function<void(std::span<const uint8_t>)> send_raw,
             std::function<void(std::span<const uint8_t>, span_writer&)> handle_udp) {
     parse_buffer pb(frame);
     pb.consume<eth::header>();
@@ -40,10 +39,10 @@ void handle(std::span<const uint8_t> frame, span_writer& tx,
     case 1:
         if (!ip_match(ip->dst, our_ip, subnet_broadcast))
             return;
-        icmp::handle(frame, tx, our_mac, our_ip, send_raw);
+        icmp::handle(frame, tx, our_mac, our_ip);
         break;
     case 2:
-        igmp::handle(frame, tx, our_mac, our_ip, send_raw);
+        igmp::handle(frame, tx, our_mac, our_ip);
         break;
     case 17:
         if (!ip_match(ip->dst, our_ip, subnet_broadcast))
diff --git a/firmware/lib/net.cpp b/firmware/lib/net.cpp
index 089ac0e..26beb4c 100644
--- a/firmware/lib/net.cpp
+++ b/firmware/lib/net.cpp
@@ -81,10 +81,10 @@ static void process_frame(std::span<const uint8_t> frame, span_writer& tx) {
 
     switch (eth_hdr.ethertype) {
     case eth::ETH_ARP:
-        arp::handle(frame, tx, state.mac, state.ip, net_send_raw);
+        arp::handle(frame, tx, state.mac, state.ip);
         break;
     case eth::ETH_IPV4:
-        ipv4::handle(frame, tx, state.mac, state.ip, IP_BROADCAST_SUBNET, net_send_raw, handle_udp);
+        ipv4::handle(frame, tx, state.mac, state.ip, IP_BROADCAST_SUBNET, handle_udp);
         break;
     }
 }
@@ -112,7 +112,7 @@ bool net_init() {
     w6300::open_socket(raw_socket, w6300::protocol::macraw, w6300::sock_flag::none);
     w6300::set_interrupt_mask(w6300::ik_sock_0);
 
-    igmp::join(igmp::PICOMAP_DISCOVERY_GROUP, state.mac, state.ip, net_send_raw);
+    igmp::join(igmp::PICOMAP_DISCOVERY_GROUP, state.mac, state.ip);
 
     return true;
 }