You want to find all the paths from point A to point B in a directed graph, such as the distance from A to B is smaller than N, and allowing the possibility that A = B.
Dijkstra's algorithm is taylored to find the smallest path from one point to another in a graph, and drops many all the others along the way, so to speak. Because of this, it cannot be used to find all the paths, if we include paths which overlaps.
You can achieve your goal by doing a breadth first search in the graph, keeping each branch of the covering tree in its on stack (you will get an enormous amount of them if the nodes are very well connected), and stop at depth N. All the branches which have reached B are kept aside. Once depth N has been covered, you drop all the paths which didn't reach B. The remaining ones, as well as the one kept aside put together becomes your solutions.
You may choose to add the restriction of not having cycles in your paths, in which case you would have check at each step of the search if the newly reached node is already in the path covered so far, and prune that path if it is the case.
Here is some pseudo code:
function find_paths(graph G, node A):
list<path> L, L';
L := empty list;
push path(A) in L;
for i = 2 to N begin
L' := empty list;
for each path P in L begin
if last node of P = B then push P in L'
else
for each successor S of last node in P begin
if S not in P then
path P' := P;
push S in P';
push P' in L';
endif
end
endif
end
L := L';
end
for each path P in L begin
if last node of P != B
then remove P from L
endif
end
return L;