diff --git a/j1939.page b/j1939.page index f9c593e..b9592e8 100644 --- a/j1939.page +++ b/j1939.page @@ -152,9 +152,7 @@ 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. +testj1939 can be told to print the used API calls by adding **-v** program argument. ### receive without source address @@ -181,14 +179,6 @@ 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 @@ -242,12 +232,6 @@ 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 @@ -297,13 +281,6 @@ 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 @@ -324,13 +301,6 @@ 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 @@ -345,13 +315,6 @@ 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 @@ -383,14 +346,6 @@ 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