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j1939.page: add relevant API calls

pull/66/head
Kurt Van Dijck 2013-11-28 09:56:54 +01:00
parent 7fb5f009fd
commit 234729507e
1 changed files with 47 additions and 0 deletions
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j1939.page
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@ -152,6 +152,10 @@ Most of the subsequent examples will use 2 sockets programs (in 2 terminals).
One will use CAN_J1939 sockets using *testj1939*,
and the other will use CAN_RAW sockets using cansend+candump.
Where I think it's relevant, I added the core API calls that *testj1939* used
because *testj1939* may look too generic to appreciate the degree of control
that the API exposes.
### receive without source address
Do in terminal 1
@ -177,6 +181,14 @@ In J1939, this means that ECU 0x40 sends directly to ECU 0x41
Since we did not bind to address 0x41, this traffic
is not meant for us and *testj1939* does not receive it.
*testj1939* used these calls:
sock = ret = socket(PF_CAN, SOCK_DGRAM, CAN_J1939);
ret = bind(sock, (void *)&sockname, sizeof(sockname));
while (1)
ret = recvfrom(sock, dat, sizeof(dat), 0,
(void *)&peername, &peernamelen);
### Use source address
./testj1939 can0:0x80
@ -230,6 +242,12 @@ This produces **1BFFFF80#0123456789ABCDEF** on CAN.
will produce exactly the same because **0x80** is the only
address currently assigned to **can0:** and is used by default.
*testj1939* used these calls:
sock = ret = socket(PF_CAN, SOCK_DGRAM, CAN_J1939);
ret = bind(sock, (void *)&sockname, sizeof(sockname));
ret = send(sock, dat, todo_send, 0);
### Multiple source addresses on 1 CAN device
ip addr add j1939 0x90 dev can0
@ -279,6 +297,13 @@ Specifing one during bind is therefore sufficient.
emits the very same.
*testj1939* used these calls:
sock = ret = socket(PF_CAN, SOCK_DGRAM, CAN_J1939);
ret = bind(sock, (void *)&sockname, sizeof(sockname));
ret = sendto(sock, dat, todo_send, 0,
(void *)&peername, sizeof(peername));
### Emit different PGNs using the same socket
The PGN is provided in both __bind( *sockname* )__ and
@ -299,6 +324,13 @@ emits **1B214080#0123456789ABCDEF** .
It makes sometimes sense to omit the PGN in __bind( *sockname* )__ .
*testj1939* used these calls, even for the broadcasted transmission:
sock = ret = socket(PF_CAN, SOCK_DGRAM, CAN_J1939);
ret = bind(sock, (void *)&sockname, sizeof(sockname));
ret = sendto(sock, dat, todo_send, 0,
(void *)&peername, sizeof(peername));
### Larger packets
J1939 transparently switches to *Transport Protocol* when packets
@ -313,6 +345,13 @@ emits:
18EBFF80#02EF0123456789AB
18EBFF80#03CDEF01234567
*testj1939* used these same calls:
sock = ret = socket(PF_CAN, SOCK_DGRAM, CAN_J1939);
ret = bind(sock, (void *)&sockname, sizeof(sockname));
ret = sendto(sock, dat, todo_send, 0,
(void *)&peername, sizeof(peername));
The fragments for broadcasted *Transport Protocol* are seperated
__50ms__ from each other.
Destination specific *Transport Protocol* applies flow control
@ -344,6 +383,14 @@ emits
1801FF80#0123456789ABCDEF
0C02FF80#0123456789ABCDEF
*testj1939* used these calls for modified priority:
sock = ret = socket(PF_CAN, SOCK_DGRAM, CAN_J1939);
ret = setsockopt(sock, SOL_CAN_J1939, SO_J1939_SEND_PRIO,
&todo_prio, sizeof(todo_prio));
ret = bind(sock, (void *)&sockname, sizeof(sockname));
ret = send(sock, dat, todo_send, 0);
### using connect
### advanced filtering