[PATCH] ipcpd: Fix MTU handling in eth

From: Dimitri Staessens <dimitri.staessens@xxxxxxxx>
To: ouroboros@xxxxxxxxxxxxx
Date: Tue, 12 Jun 2018 19:23:57 +0200

This fixes the MTU handling in eth. Buffers are now allocated to
smaller size.

Signed-off-by: Dimitri Staessens <dimitri.staessens@xxxxxxxx>
---
src/ipcpd/eth/eth.c | 38 ++++++++++++++++++++++----------------
1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/src/ipcpd/eth/eth.c b/src/ipcpd/eth/eth.c
index 8ef1153..c76ef60 100644
--- a/src/ipcpd/eth/eth.c
+++ b/src/ipcpd/eth/eth.c
@@ -93,10 +93,9 @@
#include <net/bpf.h>
#endif

-#define MAC_SIZE             6
#ifdef __linux__
#ifndef ETH_MAX_MTU          /* In if_ether.h as of Linux 4.10. */
-#define ETH_MAX_MTU          65535
+#define ETH_MAX_MTU          0xFFFFU
#endif /* ETH_MAX_MTU */
#ifdef BUILD_ETH_DIX
#define ETH_MTU              eth_data.mtu
@@ -110,6 +109,7 @@
#define ETH_MTU_MAX          ETH_MTU
#endif /* __linux__ */

+#define MAC_SIZE             6
#define ETH_TYPE_LENGTH_SIZE sizeof(uint16_t)
#define ETH_HEADER_SIZE      (2 * MAC_SIZE + ETH_TYPE_LENGTH_SIZE)

@@ -121,21 +121,22 @@
#define DIX_HEADER_SIZE      (DIX_EID_SIZE + DIX_LENGTH_SIZE)
#define ETH_HEADER_TOT_SIZE  (ETH_HEADER_SIZE + DIX_HEADER_SIZE)
#define MAX_EIDS             (1 << (8 * DIX_EID_SIZE))
-#define ETH_MAX_SDU_SIZE     (ETH_MTU_MAX - DIX_HEADER_SIZE)
-#define ETH_FRAME_SIZE       (ETH_HEADER_TOT_SIZE + ETH_MAX_SDU_SIZE)
+#define ETH_MAX_SDU_SIZE     (ETH_MTU - DIX_HEADER_SIZE)
+#define ETH_FRAME_SIZE       (ETH_HEADER_SIZE + ETH_MTU_MAX)
#elif defined(BUILD_ETH_LLC)
#define THIS_TYPE            IPCP_ETH_LLC
#define MGMT_SAP             0x01
#define LLC_HEADER_SIZE      3
#define ETH_HEADER_TOT_SIZE  (ETH_HEADER_SIZE + LLC_HEADER_SIZE)
#define MAX_SAPS             64
-#define ETH_MAX_SDU_SIZE     (ETH_MTU_MAX - LLC_HEADER_SIZE)
-#define ETH_FRAME_SIZE       (ETH_HEADER_TOT_SIZE + ETH_MAX_SDU_SIZE)
+#define ETH_MAX_SDU_SIZE     (ETH_MTU - LLC_HEADER_SIZE)
+#define ETH_FRAME_SIZE       (ETH_HEADER_SIZE + ETH_MTU_MAX)
#endif

#define ALLOC_TIMEO          10    /* ms */
#define NAME_QUERY_TIMEO     2000  /* ms */
#define MGMT_TIMEO           100   /* ms */
+#define MGMT_FRAME_SIZE      512

#define FLOW_REQ             0
#define FLOW_REPLY           1
@@ -184,7 +185,7 @@ struct ef {
struct mgmt_frame {
         struct list_head next;
         uint8_t          r_addr[MAC_SIZE];
-        uint8_t          buf[ETH_FRAME_SIZE];
+        uint8_t          buf[MGMT_FRAME_SIZE];
};

struct {
@@ -375,7 +376,7 @@ static int eth_ipcp_send_frame(const uint8_t * dst_addr,

         assert(frame);

-        if (len > ETH_MAX_SDU_SIZE)
+        if (len > (size_t) ETH_MAX_SDU_SIZE)
                 return -1;

         e_frame = (struct eth_frame *) frame;
@@ -840,10 +841,16 @@ static void * eth_ipcp_sdu_reader(void * o)
                 if (select(eth_data.s_fd + 1, &fds, NULL, NULL, NULL) < 0)
                         continue;
                 assert(FD_ISSET(eth_data.s_fd, &fds));
-                if (ipcp_sdb_reserve(&sdb, eth_data.mtu))
+                if (ipcp_sdb_reserve(&sdb, ETH_MTU))
                         continue;
-                buf = shm_du_buff_head(sdb);
-                frame_len = recv(eth_data.s_fd, buf, ETH_FRAME_SIZE, 0);
+                buf = shm_du_buff_head_alloc(sdb, ETH_HEADER_TOT_SIZE);
+                if (buf == NULL) {
+                        log_dbg("Failed to allocate header.");
+                        ipcp_sdb_release(sdb);
+                        continue;
+                }
+                frame_len = recv(eth_data.s_fd, buf,
+                                 ETH_MTU + ETH_HEADER_TOT_SIZE, 0);
     #endif
                 if (frame_len <= 0) {
                         ipcp_sdb_release(sdb);
@@ -894,11 +901,8 @@ static void * eth_ipcp_sdu_reader(void * o)

                 if (ssap == MGMT_SAP && dsap == MGMT_SAP) {
#endif
-                        pthread_mutex_lock(&eth_data.mgmt_lock);
-
                         frame = malloc(sizeof(*frame));
                         if (frame == NULL) {
-                                pthread_mutex_unlock(&eth_data.mgmt_lock);
#ifndef HAVE_NETMAP
                                 ipcp_sdb_release(sdb);
#endif
@@ -907,6 +911,8 @@ static void * eth_ipcp_sdu_reader(void * o)

                         memcpy(frame->buf, &e_frame->payload, length);
                         memcpy(frame->r_addr, e_frame->src_hwaddr, MAC_SIZE);
+                        pthread_mutex_unlock(&eth_data.mgmt_lock);
+
                         list_add(&frame->next, &eth_data.mgmt_frames);
                         pthread_cond_signal(&eth_data.mgmt_cond);
                         pthread_mutex_unlock(&eth_data.mgmt_lock);
@@ -979,7 +985,7 @@ static void * eth_ipcp_sdu_writer(void * o)
                 pthread_rwlock_rdlock(&eth_data.flows_lock);
                 while ((fd = fqueue_next(eth_data.fq)) >= 0) {
                         if (ipcp_flow_read(fd, &sdb)) {
-                                log_err("Bad read from fd %d.", fd);
+                                log_dbg("Bad read from fd %d.", fd);
                                 continue;
                         }

@@ -987,7 +993,7 @@ static void * eth_ipcp_sdu_writer(void * o)

                         if (shm_du_buff_head_alloc(sdb, ETH_HEADER_TOT_SIZE)
                             == NULL) {
-                                log_err("Failed to allocate header.");
+                                log_dbg("Failed to allocate header.");
                                 ipcp_sdb_release(sdb);
                         }
#if defined(BUILD_ETH_DIX)
--
2.17.1

[PATCH] ipcpd: Fix MTU handling in eth

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