Merge pull request #2919 from cesanta/frag

Fix IP fragmentation checks for big-endian CPUs

mongoose.c

@@ -4970,8 +4970,8 @@ struct ip {
   uint16_t len;   // Length
   uint16_t id;    // Unused
   uint16_t frag;  // Fragmentation
-#define IP_FRAG_OFFSET_MSK 0xFF1F
-#define IP_MORE_FRAGS_MSK 0x20
+#define IP_FRAG_OFFSET_MSK 0x1fff
+#define IP_MORE_FRAGS_MSK 0x2000
   uint8_t ttl;    // Time to live
   uint8_t proto;  // Upper level protocol
   uint16_t csum;  // Checksum
@@ -5145,8 +5145,8 @@ static struct ip *tx_ip(struct mg_tcpip_if *ifp, uint8_t *mac_dst,
   memcpy(eth->src, ifp->mac, sizeof(eth->src));  // Use our MAC
   eth->type = mg_htons(0x800);
   memset(ip, 0, sizeof(*ip));
-  ip->ver = 0x45;   // Version 4, header length 5 words
-  ip->frag = 0x40;  // Don't fragment
+  ip->ver = 0x45;               // Version 4, header length 5 words
+  ip->frag = mg_htons(0x4000);  // Don't fragment
   ip->len = mg_htons((uint16_t) (sizeof(*ip) + plen));
   ip->ttl = 64;
   ip->proto = proto;
@@ -5706,7 +5706,8 @@ static void rx_tcp(struct mg_tcpip_if *ifp, struct pkt *pkt) {
 }
 
 static void rx_ip(struct mg_tcpip_if *ifp, struct pkt *pkt) {
-  if (pkt->ip->frag & IP_MORE_FRAGS_MSK || pkt->ip->frag & IP_FRAG_OFFSET_MSK) {
+  uint16_t frag = mg_ntohs(pkt->ip->frag);
+  if (frag & IP_MORE_FRAGS_MSK || frag & IP_FRAG_OFFSET_MSK) {
     if (pkt->ip->proto == 17) pkt->udp = (struct udp *) (pkt->ip + 1);
     if (pkt->ip->proto == 6) pkt->tcp = (struct tcp *) (pkt->ip + 1);
     struct mg_connection *c = getpeer(ifp->mgr, pkt, false);
@@ -5870,7 +5871,8 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t now) {
 
   // Process timeouts
   for (c = ifp->mgr->conns; c != NULL; c = c->next) {
-    if ((c->is_udp && !c->is_arplooking) || c->is_listening || c->is_resolving) continue;
+    if ((c->is_udp && !c->is_arplooking) || c->is_listening || c->is_resolving)
+      continue;
     struct connstate *s = (struct connstate *) (c + 1);
     uint32_t rem_ip;
     memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
@@ -9475,6 +9477,7 @@ int mg_aes_gcm_decrypt(unsigned char *output, const unsigned char *input,
 
 
 
+
 #if MG_TLS == MG_TLS_BUILTIN
 
 #define CHACHA20 1
@@ -9557,15 +9560,6 @@ struct tls_data {
   struct tls_enc enc;
 };
 
-#define MG_LOAD_BE16(p) ((uint16_t) ((MG_U8P(p)[0] << 8U) | MG_U8P(p)[1]))
-#define MG_LOAD_BE24(p) \
-  ((uint32_t) ((MG_U8P(p)[0] << 16U) | (MG_U8P(p)[1] << 8U) | MG_U8P(p)[2]))
-#define MG_STORE_BE16(p, n)           \
-  do {                                \
-    MG_U8P(p)[0] = ((n) >> 8U) & 255; \
-    MG_U8P(p)[1] = (n) &255;          \
-  } while (0)
-
 #define TLS_RECHDR_SIZE 5  // 1 byte type, 2 bytes version, 2 bytes length
 #define TLS_MSGHDR_SIZE 4  // 1 byte type, 3 bytes length
 

mongoose.h

@@ -472,7 +472,7 @@ typedef enum { false = 0, true = 1 } bool;
 #pragma comment(lib, "advapi32.lib")
 #else
 #include <bcrypt.h>
-#if defined(_MSC_VER) 
+#if defined(_MSC_VER)
 #pragma comment(lib, "bcrypt.lib")
 #endif
 #endif
@@ -1112,6 +1112,15 @@ bool mg_path_is_sane(const struct mg_str path);
 #define MG_IPADDR_PARTS(ADDR) \
   MG_U8P(ADDR)[0], MG_U8P(ADDR)[1], MG_U8P(ADDR)[2], MG_U8P(ADDR)[3]
 
+#define MG_LOAD_BE16(p) ((uint16_t) ((MG_U8P(p)[0] << 8U) | MG_U8P(p)[1]))
+#define MG_LOAD_BE24(p) \
+  ((uint32_t) ((MG_U8P(p)[0] << 16U) | (MG_U8P(p)[1] << 8U) | MG_U8P(p)[2]))
+#define MG_STORE_BE16(p, n)           \
+  do {                                \
+    MG_U8P(p)[0] = ((n) >> 8U) & 255; \
+    MG_U8P(p)[1] = (n) &255;          \
+  } while (0)
+
 #define MG_REG(x) ((volatile uint32_t *) (x))[0]
 #define MG_BIT(x) (((uint32_t) 1U) << (x))
 #define MG_SET_BITS(R, CLRMASK, SETMASK) (R) = ((R) & ~(CLRMASK)) | (SETMASK)

src/arch_rtthread.h

@@ -1,24 +1,24 @@
-#pragma once
-
-#if MG_ARCH == MG_ARCH_RTTHREAD
-
-#include <rtthread.h>
-#include <ctype.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <sys/socket.h>
-#include <sys/select.h>
-#include <stdarg.h>
-#include <stdbool.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <time.h>
-
-#ifndef MG_IO_SIZE
-#define MG_IO_SIZE 1460
-#endif
-
-#endif // MG_ARCH == MG_ARCH_RTTHREAD
+#pragma once
+
+#if MG_ARCH == MG_ARCH_RTTHREAD
+
+#include <rtthread.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <sys/select.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <time.h>
+
+#ifndef MG_IO_SIZE
+#define MG_IO_SIZE 1460
+#endif
+
+#endif // MG_ARCH == MG_ARCH_RTTHREAD

src/net_builtin.c

@@ -48,8 +48,8 @@ struct ip {
   uint16_t len;   // Length
   uint16_t id;    // Unused
   uint16_t frag;  // Fragmentation
-#define IP_FRAG_OFFSET_MSK 0xFF1F
-#define IP_MORE_FRAGS_MSK 0x20
+#define IP_FRAG_OFFSET_MSK 0x1fff
+#define IP_MORE_FRAGS_MSK 0x2000
   uint8_t ttl;    // Time to live
   uint8_t proto;  // Upper level protocol
   uint16_t csum;  // Checksum
@@ -223,8 +223,8 @@ static struct ip *tx_ip(struct mg_tcpip_if *ifp, uint8_t *mac_dst,
   memcpy(eth->src, ifp->mac, sizeof(eth->src));  // Use our MAC
   eth->type = mg_htons(0x800);
   memset(ip, 0, sizeof(*ip));
-  ip->ver = 0x45;   // Version 4, header length 5 words
-  ip->frag = 0x40;  // Don't fragment
+  ip->ver = 0x45;               // Version 4, header length 5 words
+  ip->frag = mg_htons(0x4000);  // Don't fragment
   ip->len = mg_htons((uint16_t) (sizeof(*ip) + plen));
   ip->ttl = 64;
   ip->proto = proto;
@@ -784,7 +784,8 @@ static void rx_tcp(struct mg_tcpip_if *ifp, struct pkt *pkt) {
 }
 
 static void rx_ip(struct mg_tcpip_if *ifp, struct pkt *pkt) {
-  if (pkt->ip->frag & IP_MORE_FRAGS_MSK || pkt->ip->frag & IP_FRAG_OFFSET_MSK) {
+  uint16_t frag = mg_ntohs(pkt->ip->frag);
+  if (frag & IP_MORE_FRAGS_MSK || frag & IP_FRAG_OFFSET_MSK) {
     if (pkt->ip->proto == 17) pkt->udp = (struct udp *) (pkt->ip + 1);
     if (pkt->ip->proto == 6) pkt->tcp = (struct tcp *) (pkt->ip + 1);
     struct mg_connection *c = getpeer(ifp->mgr, pkt, false);
@@ -948,7 +949,8 @@ static void mg_tcpip_poll(struct mg_tcpip_if *ifp, uint64_t now) {
 
   // Process timeouts
   for (c = ifp->mgr->conns; c != NULL; c = c->next) {
-    if ((c->is_udp && !c->is_arplooking) || c->is_listening || c->is_resolving) continue;
+    if ((c->is_udp && !c->is_arplooking) || c->is_listening || c->is_resolving)
+      continue;
     struct connstate *s = (struct connstate *) (c + 1);
     uint32_t rem_ip;
     memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));

src/tls_builtin.c

@@ -7,6 +7,7 @@
 #include "tls_chacha20.h"
 #include "tls_uecc.h"
 #include "tls_x25519.h"
+#include "util.h"
 
 #if MG_TLS == MG_TLS_BUILTIN
 
@@ -90,15 +91,6 @@ struct tls_data {
   struct tls_enc enc;
 };
 
-#define MG_LOAD_BE16(p) ((uint16_t) ((MG_U8P(p)[0] << 8U) | MG_U8P(p)[1]))
-#define MG_LOAD_BE24(p) \
-  ((uint32_t) ((MG_U8P(p)[0] << 16U) | (MG_U8P(p)[1] << 8U) | MG_U8P(p)[2]))
-#define MG_STORE_BE16(p, n)           \
-  do {                                \
-    MG_U8P(p)[0] = ((n) >> 8U) & 255; \
-    MG_U8P(p)[1] = (n) &255;          \
-  } while (0)
-
 #define TLS_RECHDR_SIZE 5  // 1 byte type, 2 bytes version, 2 bytes length
 #define TLS_MSGHDR_SIZE 4  // 1 byte type, 3 bytes length
 

src/util.h

@@ -34,6 +34,15 @@ bool mg_path_is_sane(const struct mg_str path);
 #define MG_IPADDR_PARTS(ADDR) \
   MG_U8P(ADDR)[0], MG_U8P(ADDR)[1], MG_U8P(ADDR)[2], MG_U8P(ADDR)[3]
 
+#define MG_LOAD_BE16(p) ((uint16_t) ((MG_U8P(p)[0] << 8U) | MG_U8P(p)[1]))
+#define MG_LOAD_BE24(p) \
+  ((uint32_t) ((MG_U8P(p)[0] << 16U) | (MG_U8P(p)[1] << 8U) | MG_U8P(p)[2]))
+#define MG_STORE_BE16(p, n)           \
+  do {                                \
+    MG_U8P(p)[0] = ((n) >> 8U) & 255; \
+    MG_U8P(p)[1] = (n) &255;          \
+  } while (0)
+
 #define MG_REG(x) ((volatile uint32_t *) (x))[0]
 #define MG_BIT(x) (((uint32_t) 1U) << (x))
 #define MG_SET_BITS(R, CLRMASK, SETMASK) (R) = ((R) & ~(CLRMASK)) | (SETMASK)